According to different application conditions, the bearing is configured with different groups of working clearance. In most operating conditions, the rolling bearing has an appropriate positive clearance. There are also many applications that require a negative working clearance, that is, preloading or preloading.

Preload refers to that after the bearing is assembled, a certain way is used to apply force on the inner or outer rings of the bearing, and maintain this force to make the inner and outer rings move relatively. On the one hand, it eliminates the internal clearance of the bearing, on the other hand, it forces the rolling element to contact the inner and outer rings closely, and produces certain deformation at the contact. Because this kind of deformation is not caused by bearing load, it is called pre deformation or preload.

1. Purpose of preload

(1) Increase rigidity. Such as machine tool spindle bearings, automotive differential bearings, etc;

(2) Reduce vibration and noise during operation. Such as small motor bearings.

(3) Improve the guiding accuracy of the bearing. Such as machine tool spindle bearing, measuring instrument bearing, etc.

(4) Prevent the rolling body from sliding with respect to the inner and outer ring raceways (rotation sliding, revolution sliding) caused by the inertia moment. Such as high-speed angular contact ball bearing, thrust ball bearing, etc.

(5) Keep the rolling element and the ferrule in the correct position. Such as thrust ball bearing and thrust self-aligning roller bearing installed on the horizontal shaft.

(6) Compensate the wear in operation, improve the load distribution and prolong the service life.

2. Preloading method

Positioning preload

Positioning preload is a method of fixing bearings arranged in pairs in the axial direction to impose preload on them. Once the bearing position is fixed, it will not change during operation. This helps to improve rigidity and can implement large preloads.

The method is:

1) Assemble the paired bearings with the width difference or axial clearance adjusted in advance;

2) Apply preload to the bearing with the adjusted spacer ring and gasket;

3) Use a nut or screw with adjustable axial preload. In order to verify whether the preload is appropriate, the starting friction moment shall be measured and adjusted at the same time.

Constant pressure preload

Constant pressure preload is a method to give proper preload to the bearing by using spiral spring and disc spring. In use, even if the relative position of the bearing changes due to heat or load during operation, the preload can be approximately maintained at a certain value. The preload of constant pressure preload can be obtained by adjusting the compression of coil spring, disc spring, etc.

More about Sunspeed Spherical Roller Bearing：

Sunspeed spherical roller bearing adheres to the people-oriented concept as well as the the principle of "quality first, service first", sparing no effort in achieving the long-term development of the company.

Dealing with very heavy radial and axial loads in applications prone to misalignment or shaft deflections? Meet the challenge with Sunspeed spherical roller bearings, whose high load carrying capacity and ability to accommodate misalignment help you obtain low maintenance costs and long bearing service life. Our assortment includes spherical roller bearings designed for many applications, including wind turbine main shafts, continuous casters, vibratory applications and high-speed applications, as well as bearings with Solid Oil, split bearings, roller bearing units, and, for the harshest operating environments.

Spherical roller bearings are part of the group of radial roller bearings. These self-retaining rolling bearings have two rows of rollers with a mutually curved raceway in the outer ring and two raceways inclined relative to the bearing axis in the inner ring. This raceway design allows these bearings to combine a range of characteristics, which are essential to many applications.