Well, to be technical about this answer, ball bearings are NOT used on roller skates or skateboards. This technology went out in 1975. Since then, the 608 size precision bearing has been the standard.
As for why this size was chosen: the 608 size, which has a 22mm outer circumference size, was the closest size to the existing cup size of the previous technology, which actually used ball bearings on the inner and outer axle holes in the wheels, along with cups and nuts to keep the bearings in place. That cup size was not standard, but was based on the size of the wheel itself.
As for why bearings are used in the first place: precision bearings are by far the most technologically simple, effective way for any modern round wheel, gear, propeller, turbine, disk drive, or anything else you can think of, to spin.
To limit losses in bearings through unwanted friction.
Because they make the wheel turn easier.
The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. ... Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other. ahahaha i just copied this from the internet :)
To reduce unwanted friction.
Turbochargers turn too fast for ball bearings. Sleeve bearings are typically used in this application.
Why funnel is used for dropping the ball bearing
Ball bearings
ball type
Ceramic ball bearings are used for reducing frictional rotation, and to support radial and axial loads. It helps any application looking to have higher RPM.
Ball & Roller Bearings both belongs to the category of radial contact bearings.In case of ball bearings spherical balls are used however in case of roller bearings cylindrical rollers are used.due to balls used in ball bearings there is a point contact is made whether it is line contact in roller.
i think its either iron or steal
Faulty ball bearings lead to bearing failure.
Generally, a ball bearing is used when speed is important; a roller bearing is used more often when load is most important.
in machineare parts
Ball bearings are polished by using an abrasive cloth. Before the bearings can be polished, the polishing paste must first be applied to the ball bearing.