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Four Point Contact Ball Bearing Application
- Oct 29, 2018 -

The four point contact ball bearing uses axially asymmetric races. 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. So the angle of contact on the inner race is the same as that on the outer race. 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. 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. 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. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). These materials significantly reduce centrifugal force and function well in high temperature environments. They also tend to wear in a similar way to bearing steel—rather than cracking or shattering like glass or porcelain. 

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Thanks to a unique ball path geometry that produces twice as many contact points, a four point contact bearing can resist radial, thrust and moment loads individually or in any combination. It has one row of balls with an inner race and an outer race. The ball grooves are generated from two centers, with each radius slightly larger than the ball radius. Contact angles are typically 45° off the radial centerline, but can be varied to suit the application.

It’s widely used for slewing conveyer,welding manipulator,light & medium duty crane,excavator,and other construction machinery.In many applications a four point contact ball bearing is combined with a radial bearing such as a cylindrical roller bearing. Here, it is crucial that the four point contact ball bearing only takes axial load. ... To avoid rotation of the outer ring, most bearings are supplied with two locating slots in the outer ring.

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Jiangsu Shuangzheng Machinery Company offers a wide selection of standard and custom four point contact ball bearings, including:

1. more than 130 standard models slewing bearing

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2. five series (01,WD-23,WD-06, HS and Q ) of slewing ring bearings, geared and non-geared, in O.D.'s from 200 to 5000mm.