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some bloke said:Summary: a central motor, inside the wheel, fixed to the frame. the wheel goes around the outside, but can also move up and down for suspension purposes. how best to transfer the drive?
I'm brainstorming how to make an electric motorbike, making as much use of the available space as possible to allow for as many batteries to be fitted as possible.
Batteries aren't relevant right now; my focus is on the final drive at the back of the bike.
To maximise space, I want to fit the motor inside the rear wheel - this seemed the sensible place for it, it's already round and it's where the drive needs to go. it also means one less chain / transmission to worry about, and can help make the overall look of the bike a lot cleaner.
And maybe the main issue would be the increased wheel weight and MOI, as opposed to unsprung weight. Accelerating that puppy is going to take some extra work!berkeman said:Obvious issue with this design is the penalty in unsprung weight, it would seem...?
That may not be a big deal for all users. Lots of us like to ride slowly. In developed areas, the bumps at curb cuts and sidewalk seams are an annoyance.berkeman said:And maybe the main issue would be the increased wheel weight and MOI, as opposed to unsprung weight. Accelerating that puppy is going to take some extra work!
berkeman said:Obvious issue with this design is the penalty in unsprung weight, it would seem...?
As for the unsprung weight it's quite the opposite, it's at its minimal value (the rim and tire).berkeman said:And maybe the main issue would be the increased wheel weight and MOI, as opposed to unsprung weight. Accelerating that puppy is going to take some extra work!
Now that's an interesting point. If they cycle and dissipate heat constantly, then it becomes more like an exercise bike.sandy stone said:Also, the suspension components are cycling constantly due to vehicle weight, even when rolling on a flat surface. Sounds like a lot of extra wear and tear.
jack action said:As for the unsprung weight it's quite the opposite, it's at its minimal value (the rim and tire).
But I didn't think about the MOI and that is certainly a negative factor.
What I find also interesting is that the suspension geometry affects only the vertical motion, which is what it is supposed to do (no toe, camber, caster change or tire scrub as it moves up & down). But it might also become problematic to handle lateral forces in extreme cases.
In-wheel suspension is a type of suspension system that is integrated into the wheels of a vehicle. This means that the shock absorbers, springs, and other components are located inside the wheel itself, rather than being attached to the chassis of the vehicle.
In-wheel suspension offers several benefits, including improved handling and stability, reduced weight and unsprung mass, and increased interior space in the vehicle. It also allows for more precise control of each wheel, resulting in better traction and overall performance.
In-wheel suspension typically uses a combination of springs and shock absorbers to absorb the impact of bumps and uneven surfaces. The springs compress and expand as the wheel moves up and down, while the shock absorbers dampen the movement to provide a smoother ride.
In-wheel suspension has been around for several decades, but it has recently gained more attention as electric vehicles become more popular. In-wheel suspension is often used in electric vehicles because it allows for more space for batteries and other components.
While in-wheel suspension offers many benefits, there are also some potential drawbacks. It can be more complex and expensive to design and maintain, and it may not be suitable for all types of vehicles or terrains. Additionally, the added weight of the suspension components in the wheels can affect fuel efficiency.