Four-point angular contact ball bearings QJ 218 N2MA

Four-Point Contact Ball Bearings QJ218-N2-Ma

QJ218-N2-MA belongs to a four-point contact ball bearing. It has an inner diameter of 90mm, an outer diameter of 160mm, a thickness of 30mm, a single-row bearing with locating grooves, a solid brass cage and an outer ring guide.

Structural Features:

The inner and outer raceways of four-point contact ball bearings QJ218-N2-MA have a peach-shaped cross-section. When there is no load or only pure radial load, the steel ball and the collar present a four-point contact between them, which is also the origin of the name of the bearing.

The inner or outer ring of the bearing is made of two half-rings precisely fitted together, resulting in a very small radius of curvature of the grooves of the overall periphery or inner ring. This design allows the balls and the inner and outer rings to be in contact at all four "points", thus increasing the radial load capacity while at the same time being able to withstand large axial loads in both directions in a compact size.

The four-point contact ball bearings designed by QJ have a contact angle of 35° or 45°. The inner ring is a split inner ring, which allows a larger number of balls to be loaded into the bearing, thus increasing the load-carrying capacity of the bearing.

Performance Characteristics:

Four-point contact ball bearings QJ218-N2-MA can withstand radial loads and bi-directional axial loads and limit axial displacement in both directions. Compared with other ball bearings, when the radial clearance is the same, four-point contact ball bearings have smaller axial clearance and higher limiting speed.

The permissible rotational speed is high, and the operation is smooth. Its double half-ring can be removed from the complete set of bearings and mounted separately, which makes it particularly useful in applications (e.g. engines) that require high rotational speeds and are subjected to large radial and axial loads.

Under normal operating conditions, regardless of the axial load in any direction, a contact angle can be formed; the steel ball and the inner and outer raceways are each contacted at one point, which helps to avoid large sliding friction in the contact area.