How do ball bearings reduce friction in machinery?

Answer 1

Because rolling friction is much less than sliding friction.

Answer 2

The actual area of the surface of the balls in contact with the stationary surfaces is very small thereby decreasing friction to a very low level.
Oil in the system reduces friction further, keeps the bearings cool, and seals against rusting.

Answer 3

Because ball bearings reduce the area of the bearing surface and the balls rotate in the bearing so there is essentially no sliding friction. (A ball rolling on a plane surface is theoretically a point contact.) The problem is that the pressures are enourmous with all the load on that one point. So ball bearings are made of very hard materials. .

Answer 4

They do it by eliminating sliding and replaces it with rolling motion. Sliding friction is generally much greater than rolling friction. Go drag a 100 lbs bag of Portland cement around the yard. Then use a wheel barrow. Get the picture?

Answer 5

The provide less surface area for friction to occur, and accomplish this by providing smooth spheres, and a smooth inner and outer metal surface for the spheres to roll against.

Answer 6

ballbearings roll between two surfaces and when grease is introduced the friction declines dramatically thus, less friction and longer life of the two surfaces.

Answer 7

It reduces the contact surface.

Answer 8

they roll.on the shaft ,sleeve bearing needs lots of grease because the shaft slides on it,like rubbing you finger across the desk