I am Eldert Zeinstra from the Netherlands and i am 21 years old I study engineering in Groningen.
After considering for a while Danny Bokma and Ray Blokker persuade me to build a electric skateboard.
I though it was great fun to drive and also very useful in the city or at the campus.
I have absolutely no experience with skating or anything like it.
But I do have a little experience with solar-boat racing where we also use brushless motor’s and lithium polymer battery’s hope this will help while building and designing
The idea is to build a reliable hub motor that still has a lot of rubber to squeeze to provide a smooth ride.
The first components have arrived with the post
Now i have these parts i can start designing the aluminium hub.
when i have finished some solidworks drawings i wil show them to u.
I did a version very similar long ago. If you’re not planning to modify the wheel there’s not much room. I did it so the wheel wouldn’t have to be cut/modified and Therefore used smaller bearings and they deteriorated quickly. Also skate hangers aren’t straight after they cast the aluminum around the axle and if the rotor is supported with bearings sitting on the axle yet the stator is far away they can misalign by too much. It’s super fun and look forward to seeing how you do it. Maybe get the motors lever uses as they have a skirt bearing that allows a lot more room. Expect to spend eons on a lathe and mill trying to get things precise with an imprecise skate axle though. Maybe I’m wrong and u have a better approach than what I did.
I think that when something is well thought out it mostly automatically looks good.
why do the people do not like it?
I do modify the wheel to fit the aluminium hub inside. but you are correct the motor is not really inside the wheel.
inline or direct drive motor is probably a better name:)
there was only one motor on the photo but I have 2 of course i will make it a dual drive. I hate asymmetric things
can you post pics of the different parts separated? specifically the connection between the rubber and the rotor looks difficult. how to shape the wheel and connect it seems a lot of work. if you do it with the other motors that cavon uses with the skirt bearing then you can have the rotor supported on both sides with a bearing and not be as vulnerable to bangs and more importantly you can be assured the stator and rotor will line up precisely . Maybe you haven’t seen on endless-sphere someone named stylz first used this motor with the skirt bearing and explained how to do it.
Really like this, i can’t wait to hear how this motors work out.
You could pot windings, and leave the backside of the motor open, that would look sick
O nordle is excited and pulled out the upside down purple bug!
The kv of those motors, are u going to reterminate them wye to drop the kv? I’m dying to convince someone to do it strand by strand with an led and little battery if you’re up in the air about it.
I wonder how long this is going to take you. I spent like 6 months doing it.
All these direct drive obsessed people are coming out of the woodwork in this thread. I bet you all like to use one tool for everything too trying to make it work. I say that because in retrospect taking a motor apart and then putting it back together is the harder more diy way
This is a classic attempt.
Beware of how skate axles aren’t straight as I say though without a bearing on either side to keep it lined up with the rotor. To get the stator and rotor aligned because of this I ended up wrapping the stator in 2 layers of duct tape while epoxying it to the hanger, then sliding the rotor with its wheel and the supporting bearings on the axle on top of it. This was so it would be positioned ok even though the axle is bent a bit. then when epoxy cured take the duct tape out and put the motor back together. Not a bad way to fix the stator position though and my failure was tiny bearings
Here is a screenshot of the aluminium hub.
The center of the wheel needs to be machined out to diameter of 30 mm. then only a piece of the spokes remains.
When everything is going as planned the aluminium hub will need a slight press to fit inside the wheel.
The wheel will be secured by a 3 mm plate with 6 m3 bolts.
From the bearings to the outer ring of the motor the max distance is just over 40 mm. this shouldn’t be a problem if the bearing aren’t worn out right?
Or do skate bearings normally have a lot more backlash than industrial bearings?
Of course everything needs to be aligned pretty well, but i don’t think that this will be a problem.
Because you can’t replace them with of the shelf wheels? or do you just don’t like machining? haha
Yes they are not round en concentric with the steel shaft. i have to machine it to a bit smaller diameter so the adapter for the stator can slide over it.
i am not sure if it is a good idea to fix the stator with a press/lLoctite.
maybe its better to use a keyway and a smal bolt to secure it?
Yep, and the machining will probably cost like 10 minutes are so.
I always find it scary to glue parts that gets a dynamical load. there is always a change that it will suddenly break without any warning. Maybe i am just way to cautious.
diameter is 63 and its 30 mm long. no idea where the 55 stands for.
I’m assuming you’re going to lathe down the hanger to slide the stator on. You say there’s 4cm distance between where the bearings sit and the beginning of the rotor. then the rotor will add more distance that needs to be aligned. maybe spin the hanger on the lathe now to see just how much it is going to be off before you commit to a method. if you glue the stator down you could adjust it’s orientation in relation to the rotor a bit to get it aligned better. . I had planned to just lathe it down and slide and pin down the stator but the bent hanger was too much and resorted to aligning the stator by slightly over machining the hanger and filling the void with thick glue. Glue is super strong. .
Yes that’s right. the bushing that is pressed inside the stator will have a sliding fit on the hanger.
I will leave some space for an additional bearing on that bushing. Don’t know if i can cal it a skirt bearing?
So far is i now this hanger isn’t that bend but i will check it before i lathe it down
I have done some machining on the hubs yesterday.
unfortunately the 4mm mill was vibrating caused a rough finish.
! Keep us posted!
of course i will make it a dual drive. I hate asymmetric things
The bell is 63x30 mm
the stator diameter is 53 mm
