Ball Mate in assembly

aaron_2

I created a bearing which I shared publicly. I was trying to create the mates so that it would work properly. Unfortunately I was unable to figure it out.  Is there anyone who would like to help me on this?

andrew_troup

The cage should rotate at half the speed of whichever raceway spins. A gear mate will achieve this, as billy says.

pete_yodis

Andrew_Troup said:

The cage should rotate at half the speed of whichever raceway spins. A gear mate will achieve this, as billy says.

That's partially why I asked about the cage.  If the cage has circular pockets, then there would also not be a need for sketch driven mates for the revolute on the balls.

lougallo

Can you copy the URL from the publicly shared doc so we can take a look?

aaron_2

hey Lou. Not sure exactly what to copy.

pete_yodis

aaron53560 said:

hey Lou. Not sure exactly what to copy.

The web adress from the browser when you are inside and editing your public document.

aaron_2

https://cad.onshape.com/documents/5a5000a1686a4767bc5c86a9/w/946a229860004f1c9160de17/e/94ecc8e109f94347a95b0f6f

pete_yodis

How complicated do you want the motion of the bearing assembly to be?  Should the balls rotate inside the raceways?

aaron_2

That's what my goal was. the ball mate was about the only thing i couldn't figure out.

pete_yodis

Does the bearing have a cage?

billy2

aaron53560 seems like you'll have to reference sketch geometry for the mate since you don't have proper 3d geometry to make a mate connector assignment.



I too think you'll need a revolute mate connector to the bearing race and then mate the ball bearings to race.

You could define a vector in the ball bearing that represents the rotating axis as shown above and rotate one bearing about the center. But then would the pattern update properly? This is really bad design intent and would not win you any prizes at a county fair if you were to show this approach off in public.

Put the raceway in the model, or at a minimum, add a sketch that represents a raceway that'll rotate about the inner bearing and attach the bearing to a rotating sketch. You won't be able to see the balls roll, but you could add a gear mate connector between the sketch and the ball bearings. If this is really your ambition, try building a planetary gear stack-up. This way you can see the planetary gears rotate.

FYI, there's a big push to have vector layout sketches to help define assemblies & motion. In your case I think this approach would have helped you out. In other words, create a layout sketch for the motion, and then hang the masses on the layout sketch. It's a different approach than what you are experiencing and I think you're model is a great case study for this other layout sketch technique.

andrew_troup

The cage should rotate at half the speed of whichever raceway spins. A gear mate will achieve this, as billy says.

pete_yodis

Andrew_Troup said:

The cage should rotate at half the speed of whichever raceway spins. A gear mate will achieve this, as billy says.

That's partially why I asked about the cage.  If the cage has circular pockets, then there would also not be a need for sketch driven mates for the revolute on the balls.

aaron_2

This is is great. i am planning on creating a cage for it and trying that. It will be a few days before i am going to have time to get to it though. Thanks for the help, I really didn't even think about a cage when i did this.