ElectricMotorcycleForum.com
General Category => General Discussion => Topic started by: Richard230 on January 19, 2021, 04:47:02 AM
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What do you think of this? ??? https://www.motorcycle.com/mini-features/michelin-patents-rear-fender-with-built-in-auxiliary-drive-motor.html
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Extra sprung weight...
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I can understand companies patenting weird shit just in case someone else decides to build it later but I don't get why a company as large as Michelin would waste time and money on something as ridiculous as this. With the stated specs and the way it's designed it just won't work, and if it was redesigned so it did work it just wouldn't be worth it. Much easier and simpler to just use the starter motor like on a Goldwing.
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TheRan, what?
It's supposed to give a gas bike the "creep" forward backward function that an Energica has.
Help to get into and out of tight spots.
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TheRan, what?
It's supposed to give a gas bike the "creep" forward backward function that an Energica has.
Help to get into and out of tight spots.
That's what a goldwing already does, as theran said.
This patent achieves the same result but with added complexity. I would assume it also requires the fender/license plate holder to be much stronger and more robust than the ones currently on production bikes.
It's not a totally terrible idea, and it should work, but it doesn't seem like the best most practical solution. Nor is it a problem that particularly needs being solved.
https://www.youtube.com/watch?v=2KPqpFBnkGM
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It could work, but certainly not with such a small and underpowered motor. It would essentially need a second starter motor if not something even more powerful and the structure supporting it and applying enough force to actually grip the tyre would be very large and heavy. And as they want to make it switchable (because it would be downright retarded to keep it engaged all the time) that's another mechanism to wear out and break and the mechanical advantage needed to apply the necessary force would require either a ridiculous amount of travel (think having an old fashioned car hand brake mounted to your bike) or someone very strong to operate it. Then there are the safety concerns, if the mechanism fails and applies the roller to the tyre at high speed it could possibly jam and lock the wheel.
As Caza says, it's a solution to a problem that's already been solved in a much better way. I literally can't think of a single advantage to this thing over using the starter motor. Actually no, the only advantage it has is it can work on kick start only bikes but I don't really think it's needed on a 300 pound dual sport (and it probably wouldn't work too well on knobbies).
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"Added complexity???" It's putting a motor and battery on the outside of the bike. It doesn't involve engineering gearing changes and a transmission clutch to divert a starter motor from driving a flywheel to start an engine to driving the driveshaft to move the motorcycle. That is NOT easy. Maybe for the rider perhaps, but that takes a LOT of engineering know-how to build into the bike.
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It's more than just a motor and a battery. All that's needed to move a bike with the starter motor is a motor that can handle being run for an extended period (which exists, as evidenced by the Goldwing) and some relatively simple electronics to drive it. It doesn't need to turn a driveshaft because it can turn the engine which already turns the wheel if the transmission is in gear. One additional change, if reverse is needed, is an engagement mechanism on the starter motor's pinion that works in both directions (not that difficult). The method that Michelin has patented also requires a motor and control electronics in addition to a load of other shit. More stuff, more weight, more points of failure. I would call that (needlessly) added complexity.
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"Added complexity???" It's putting a motor and battery on the outside of the bike. It doesn't involve engineering gearing changes and a transmission clutch to divert a starter motor from driving a flywheel to start an engine to driving the driveshaft to move the motorcycle. That is NOT easy. Maybe for the rider perhaps, but that takes a LOT of engineering know-how to build into the bike.
I'm not claiming what honda did in the goldwing is easy, but they're smart people, and every other moto manufacturer has smart people as well, and could add this feature if it was necessary. It's not common, but part of that is because there's simply not a huge demand for this feature. Creep is what the friction zone is for, and on most bikes you reverse so seldom that walking the bike back is really not an issue. Keep in mind how resistant motorcycle culture is to any new tech or complexity, whether that's a DCT , ABS, throttle by wire, etc. These additions really have to be proven and well implemented before they're embraced, if they're ever embraced at all.
You're right that putting a motor on the outside of the bike sounds simple, but it's more complex than that for several reasons. As TheRan said, the motor is going to have to be a lot bigger and heavier than pictured. This requires the license plate holder/fender to become a structural element of the bike, which would add significant unsprung weight and hurt the handling characteristics of the bike. It also adds costs, from the materials of the more robust mount to the cabling to the motors themselves to the likely bigger 12v battery and motor controller. You'd also need a mechanism to make sure this motor is held sufficiently away from the tire when not in use and then provide enough pressure to grip the tire when in use. And let's not act like none of this requires engineering to make happen.
The honda solution certainly requires slightly more complexity than a bike without it, but in terms of material costs it should be much less than the fender design. And it has already been proven and implemented in a production motorcycle, so that engineering work is done and we know it works. It also keeps all of its parts internal to the motorcycle, while the Michelin motors are exposed and could more easily be damaged.
Worth noting the video I linked to is a different imlimentation than what theran is talking about. That video shows the newer goldwing with the DCT, but they were doing this for years with just the starter motor in the older goldwings.
What would be the advantage of switching to the Michelin design? The only thing that makes some sense to me is as a 3rd party accessory to retrofit heavy bikes that would benefit from reverse. But even that is a stretch, what would you have, dozens of customers?
I'm glad we're riding electrics that can implement this feature through a button and software instead of being a bigger engineering feet like this.
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Ok that's a new one for me.
For my money I wouldn't want to risk bending my starter shaft moving a thousand pound bike but I guess they have it pretty beefy.
As for the OP I think I'd attach it to the swing arm above the chain and let it move the bike from the chain with the bike in neutral. Just lower a sprocket and turn the chain. That would avoid the need for tire to roller fiction pressure.
If the small motor is set up for all torque it shouldn't have much problem. Just like winches that pull out huge Hummers and such.
All torque and very little speed.
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The torque required to move it by the chain, as with moving it by friction applied to the tyre, would be far greater than just spinning the engine over and using the transmission in first gear. Honda have been using the starter motor for reverse for over 30 years now, I'm sure if there was a better way of doing it they would have found it.
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Since when did anyone decide they actually... need something like this?
Cas :)
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People keep saying 'significant unsprung weight' and I don't know if the word 'significant' is true.
-Crissa
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All unsprung weight is significant, though you'd think by the trend of sticking numberplates and light clusters on iron bars hanging off the back of the rear axles that the current crop of engineers may have finally lost the plot. Probably the same bunch that thought underseat exhausts were a good idea. I imagine they invented inboard ventilated disc brakes and electronic anti-dive at the start of their careers. Don't worry they'll all be dead soon and sanity will return.
Cas :)
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When I saw the rear tire friction-drive electric motor patent article I immediately thought of the little generator that you would mount of a bicycle to power a headlight back in the day when I was growing up. The generator was operated by a rubber wheel rubbing against the side of the tire. Kind of makes me wonder how the possum-scraper wheel would get enough traction against the tire tread to move 600-800 pounds of bike and rider in any direction, much less up a grade, which is where it would be needed the most. And as mentioned above, having a relatively heavy weight located behind the rear axle is not something that is going to be appreciated by the motorcycle press reviewers, most of whom are former racers. ;)
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"It handles terribly as a result, but fortunately, when you inevitably stack it into a ditch as a result of its wheelbarrow-like behaviour, it's easy to reverse out."
- More Crap than News
Cas :)
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When I saw the rear tire friction-drive electric motor patent article I immediately thought of the little generator that you would mount of a bicycle to power a headlight back in the day when I was growing up. The generator was operated by a rubber wheel rubbing against the side of the tire. Kind of makes me wonder how the possum-scraper wheel would get enough traction against the tire tread to move 600-800 pounds of bike and rider in any direction, much less up a grade, which is where it would be needed the most. And as mentioned above, having a relatively heavy weight located behind the rear axle is not something that is going to be appreciated by the motorcycle press reviewers, most of whom are former racers. ;)
That's pretty much the main issue that kills the idea, you'll need to apply so much force to maintain traction that it's going to require a lot of material (weight) to be strong enough and require a beefy (heavy and awkward) mechanism to engage and disengage the roller. They could increase the size of the roller for more contact area but then you have more weight, an even bigger tumour hanging off the back of the bike, and you'll require an even more powerful motor (even more weight and money) because the bigger roller will have less torque.
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I think it probably requires rather less force than you'd think.
Cas :)
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People keep saying 'significant unsprung weight' and I don't know if the word 'significant' is true.
-Crissa
Everyone has a different feel for what "significant" can be, but it's just a fact that unsprung weight effects handling. How much it matters to you is going to vary depending on the bike, the rider, the type of riding they are doing, among other factors.
If you look at the sondors metacycle, it has a big hub motor which means unsprung weight that will no doubt effect its handling. But the overall bike is so light and small and intended for light city riding and beginner riders, so I doubt any of its audience would care to notice the handling difference, most of them wouldn't even have a basis for comparison. Ignorance is bliss! Similarly, most scooters have their entire CVT and even the motor built into the swingarm, which is all unsprung weight, but ask a scooter rider if they care.
But the heavier gas bikes that would benefit from this are almost all being ridden by more seasoned riders that know a lot more of the nuance in motorcycling handling, and they would very likely notice and care about the difference. Likewise because they have an overall heavier bike and are going faster speeds, that nuance in handling is going to have a bigger effect on their ride and safety.
And someone who goes to the track is worrying about the alloy of their wheels and the speedholes and material of their rear sprocket, because to them every gram makes a difference.
For my money I wouldn't want to risk bending my starter shaft moving a thousand pound bike but I guess they have it pretty beefy.
As for the OP I think I'd attach it to the swing arm above the chain and let it move the bike from the chain with the bike in neutral. Just lower a sprocket and turn the chain. That would avoid the need for tire to roller fiction pressure.
If the small motor is set up for all torque it shouldn't have much problem. Just like winches that pull out huge Hummers and such.
All torque and very little speed.
Yeah obviously the starter motor in a goldwing is going to be beefy enough to handle the feature. Bikes are designed as a complete system and Honda took this into consideration, so it's a non-issue.
The chain attachment idea might work but seems just as complex as the patent.
Since when did anyone decide they actually... need something like this?
Cas :)
This is where I'm at. Is it a nice feature to have, sure. But we've gone without it for decades and the sacrifices and cost to produce it don't seem to be worth the marginal benefit nor the obvious downsides. Even Zero doesn't bother to add it and all they need is software and a button, but it's just not an in-demand feature.
Honda's simpler version of this feature on the goldwing works, and makes sense for that bike, but even they haven't bothered to try to bring it to the rest of their lineup. Even their other DCT bikes don't have that version of the feature.
All unsprung weight is significant, though you'd think by the trend of sticking numberplates and light clusters on iron bars hanging off the back of the rear axles that the current crop of engineers may have finally lost the plot. Probably the same bunch that thought underseat exhausts were a good idea. I imagine they invented inboard ventilated disc brakes and electronic anti-dive at the start of their careers. Don't worry they'll all be dead soon and sanity will return.
Cas :)
Swingarm plate holders aren't going anywhere as long as looks and perceived status drive sales instead of pure practicality and function. It's specifically not an engineering feature but a style feature, to meet DOT regulations without spoiling the "concept" look of a bike. Where form-over -function meets regulation, we get the fender-plate. Doesn't matter who dies, this design isn't going anywhere.
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I want one NOW!
NOW NOW NOW!
Take all my money so that I can get one NOW!
I'M DYING HERE! PLEEEEEEEEASE!
Wait, what is this thread about?
Oh, the fender thing.
Meh.
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If you look at the sondors metacycle, it has a big hub motor which means unsprung weight that will no doubt effect its handling. But the overall bike is so light and small and intended for light city riding and beginner riders, so I doubt any of its audience would care to notice the handling difference, most of them wouldn't even have a basis for comparison. Ignorance is bliss! Similarly, most scooters have their entire CVT and even the motor built into the swingarm, which is all unsprung weight, but ask a scooter rider if they care.
This scooter rider DOES care. Most of the time I don't really notice it on my XMAX, but the first time I aggressively entered a bumpy turn I found myself all over the road and thanking GOD there wasn't a car coming in the opposite direction. That heavy swingarm/engine/transmission structure absolutely SUCKS at responding to repetitive bumps in turns. My old TMAX (which mounts the engine in the frame like a motorcycle and drove the rear wheel with an enclosed chain) had no problems on that same stretch of road.
So despite the fact that Yamaha bills the XMAX 300 as a "sport scooter" it is really better at relaxed commuting and touring speeds.