Ball (bearing)

Bearing balls are special highly spherical and smooth balls, most commonly used in ball bearings, but also used as components in things like freewheel mechanisms. The balls come in many different grades, as defined by the American Bearing Manufacturers Association (ABMA), which defines the precision of the balls. They are manufactured in machines designed specially for the job.

In 2008, the United States produced 5.778 billion bearing balls.

Grade

Bearing balls are manufactured to a specific grade, which defines its geometric tolerances. The grades range from 2000 to 3, where the smaller the number the higher the precision. Grades are written "GXXXX", i.e. grade 100 would be "G100". and lack of defects, such as flats, pits, soft spots, and cuts. The surface smoothness is measured in two ways: surface roughness and waviness.

Size refers to how tight the tolerances are on the size, as measured by two parallel plates in contact with the ball surface. The starting size is the nominal ball diameter, which is the nominal, or theoretical, ball diameter. The ball size is then determined by measuring the ball diameter variation, which is the difference between the largest and smallest diameter measurement. For a given lot there is a lot diameter variation, which is the difference between the mean diameter of the largest ball and the smallest ball of the lot.

Ball bearing

A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.

The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. In most applications, one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other.

Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races.

History

Although roller bearings had been developed since ancient times, the first modern recorded patent on ball bearings was awarded to Philip Vaughan, a Welsh inventor and ironmaster who created the first design for a ball bearing in Carmarthen in 1794. His was the first modern ball-bearing design, with the ball running along a groove in the axle assembly.

Ball Bearing (advertisement)

Ball Bearing was a 1992 television advertisement for the Lexus ES 300, which introduced the luxury sedan to American television audiences. It was created by Team One, a unit of Saatchi & Saatchi. The advertisement showed a ball bearing rolling smoothly down the panel seams of a Lexus sedan, thus demonstrating the precise quality of its exterior elements. The television spot won awards, was emulated by subsequent commercials, and was credited for focusing industry attention on body tolerances.

Synopsis

The advertisement showed the Lexus ES 300 on an articulating stand. A lab-suited technician places a silver ball bearing on the hood seam, and lets go. The ball bearing rolls smoothly down the seam as if on a track. As the stand rotates, moving the ES 300 slowly around several axes, the ball bearing travels across the roof, grille, tail lamps, in a continuous uninterrupted motion, without falling. The narration reads, "Every sports sedan is supposed to do well in the fast lane. But what about these lanes...? At Lexus, we achieved extremely tight tolerances between all major body panels. So not only does the ES 300 look like it's put together well, it actually is put together well."