Preload and duplex installation

myonic duplex bearings are clearly marked for the correct installation position.

The purpose of preload in radial or angular contact ball bearings is to increase rigidity, improve running accuracy and minimize ball sliding at very high speeds or under high acceleration/deceleration. In general, preload is achieved in a ball bearing by exerting an axial force on the end face of the ball bearing ring.
This axial force is applied either by springs or by a predetermined axial offset of the outer ring raceway to the inner ring raceway.

Spring preload

A spring preload is generated with the aid of one or more spring elements that act with a predetermined axial force against the end face of the outer ring or the inner ring of the ball bearing. With inner ring rotation, the spring washer is pressed against the outer ring (sliding fit). With outer ring rotation, the spring washer is pressed against the inner ring (sliding fit). myonic manufactures high-precision spring washers made of stainless steel for every standard bearing in our catalog.
It is essential that the two end faces of the spring washers are very parallel to each other to ensure correct preload and avoid misalignment of the ball bearings.

Preloading of the duplex bearings

To set the preload for two or more ball bearings with greater accuracy, the rings must be manufactured as shown in the illustrations. The axial offset of the inner ring face to the outer ring face determines the desired preload. During installation, the axial offset is eliminated and the preload is thus generated.

Preloading of the “X configuration” (suffix .9f)

In the X arrangement, the distance between the outer ring raceways is smaller than the distance between the inner ring raceways.
The difference in raceway spacing arises during installation due to the elimination of a defined axial offset of the end faces. The axial offset of the inner ring face to the outer ring face is created by grinding the faces of the outer rings on one side of the ball bearing. With the X arrangement, the effective distance between the bearing centers is reduced. The lines of contact converge. The distance between the virtual pressure points
(intersection of the contact angle lines with the symmetry axis) is smaller than the track distance. This arrangement is more error-tolerant with regard to alignment of the bearing system during installation and has good rigidity.

Preloading of the “O – configuration” (suffix .9d)

In the O arrangement, the distance between the outer ring raceways is greater than the distance between the inner ring raceways.
The difference in raceway spacing arises during installation due to the elimination of a defined axial offset of the end faces. The axial offset of the inner ring face to the outer ring face is created by grinding the faces of the inner rings on one side of the ball bearing. With the O arrangement, the effective distance between the bearing centers increases. The lines of contact diverge. The distance between the virtual
pressure points (intersection of the contact angle lines with the symmetry axis) is greater than the track distance.
This arrangement is used at high speeds and to increase the tilting moment.

“Tandem arrangement” (suffix .9t)

The ball bearings can also be arranged in tandem. The contact lines run parallel and the radial and axial forces acting from the outside are evenly distributed. This arrangement offers the advantage of a higher axial load capacity in one direction. Normally another bearing or another tandem bearing group is installed at the other end of the shaft in order to absorb any axial forces acting in the opposite direction.