These materials significantly reduce centrifugal force and function well in high temperature environments. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). In high speed applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces generated by the balls changes the contact angle at the inner and outer race. The larger the contact angle (typically in the range 10 to 45 degrees), the higher the axial load supported, but the lower the radial load. Angular contact bearings better support combined loads (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. So the angle of contact on the inner race is the same as that on the outer race. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that acts to separate the races axially. A hybrid ball bearing is a bearing with ceramic balls and metal races.Īngular contact An angular contact ball bearing uses axially asymmetric races. They can be made from many different materials, including stainless steel, chrome steel, and ceramic ( silicon nitride, Si 3N 4). ![]() There are several common designs of ball bearing, each offering various performance trade-offs. Jules Suriray, a Parisian bicycle mechanic, designed the first radial style ball bearing in 1869, which was then fitted to the winning bicycle ridden by James Moore in the world's first bicycle road race, Paris-Rouen, in November 1869. His was the first modern ball-bearing design, with the ball running along a groove in the axle assembly. ![]() However, they can tolerate some misalignment of the inner and outer races.Īlthough 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. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other.īall 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. As one of the bearing races rotates it causes the balls to rotate as well. In most applications, one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). It achieves this by using at least two races to contain the balls and transmit the loads through the balls. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. A four-point angular-contact ball bearing A ball bearing for skateboard wheels with a plastic cage Wingqvist's self-aligning ball bearingĪ ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. Working principle for a ball bearing red dots show direction of rotation. Please consider expanding the lead to provide an accessible overview of all important aspects of the article. ![]() This article's lead section may be too short to adequately summarize the key points.
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