Bearings
Bearing blocks
Bearing blocks consist of a deep groove ball bearing and a cast iron housing in various shapes. The cast iron bearing blocks are most often used, but there are also other versions such as: sheet steel housings, bearing blocks made of plastic with a rust-resistant inner bearing and split bearing housings with a spherical roller bearing or a self-aligning ball bearing.
In which machines are bearing blocks frequently used?
- Farm implements
- Conveyor Belts
- Construction machinery
- Food Processing Machines
- Sorting machines
- Packaging machines
- Bottle and can filling machines
- Textile Machinery
- Fans
What type of bearing blocks are there?
- Hanging bearing blocks
- Flange bearing blocks
- Pillow bearing blocks
- Insert bearings
- Tension Bearing Blocks
Self-aligning bearing blocks
What are the two main components of self-aligning bearing blocks?
1. A cast iron housing with a spherical bore connection for a grease nipple. The housing is in one piece and constructed in such a way that the full bearing capacity of the bearing is utilized.
2. A greased, double sealed, single row deep groove ball bearing with a convex outer ring.
Built-in bearing
The internal construction and load capacity of the bearing mounted in the bearing housing corresponds to the ball bearings of series 62.. or series 63.. The inner ring, outer ring and the balls are made of through-hardened ball bearing steel 100Cr6. The cage is made of sheet steel or plastic. This is usually glass fiber reinforced polyamide 6.6.
All built-in bearings are filled with the correct amount of lubricant and require virtually no maintenance. The bearings have a groove and two lubrication holes in the outer ring so that re-lubrication is always possible. They can be used at temperatures from -20°C to +100°C.
Because the outer ring, together with the chamber of the housing, are spherical, it is possible to correct initial errors in the alignment and deflection of shafts.
Permissible skew
What is the allowed skew?
- For regreasable bearings up to ± 3°
- For non-greasable bearings up to ± 8°
- For bearings with protective cap up to ± 1°
To prevent the outer ring from rotating in the housing, the bearings are provided with a locking pin as a security. The setting angle and therefore also the self-adjustability is not affected.
How are cast iron bearing blocks assembled?
Normally the bearing blocks are delivered completely assembled. The built-in bearing is already present in the housing. Nevertheless, it is good to have knowledge of how cast iron bearing blocks are mounted. Installation is as follows:
- First, check whether the locking bolts do not protrude through the inner ring
- The bearing block is slid into the desired position
- The bearing housing is mounted on the structure
- The inner ring is secured
Locking Bolt Mounting Bearings
Normally, the use of these bearings is sufficient. It is recommended to make a center point at the places where the screws touch the shaft for extra security. It is important to tighten the bolts correctly. Too high a torque can cause deformation or even breakage, and too low a tightening torque can cause the bolts to loosen. The correct tightening torques are stated in the manufacturer's documentation.
Bearings with eccentric ring mounting
This loose ring has a recess that is off center in relation to the bore. On one side of the inner ring is a corresponding outer eccentric part. The ring is placed on the inner ring and clamped in the direction of rotation of the shaft. By tightening the locking screws, the eccentric ring is secured and the bearing is secured to the shaft.
A check must be carried out after the bearing block has been mounted. For this, the shaft is rotated by hand and felt whether everything rotates evenly. Then start the engine at a low speed and with a low load. When everything is running properly, speed and load can be increased to normal working level. It is also recommended to check the temperature of the bearing block regularly during the first hours of operation.
If the bearing block is correctly mounted, the temperature will rise for the first 2 to 3 hours and then stabilize at a certain value. If the temperature rises extremely quickly and does not stabilize, the installation may not have been carried out correctly.
