25*42*17 roller bearing NK4905

roller bearingNA4905Dimension:25*42*17

Once ordered, please inform me which type you need? .... thanks.

bearing is a roller bearing with cylindrical roller, the roller is thin and relative to its diameter. This type of roller is called a roller. Dete the small cro-section, the bearing still has a high load bearing capacity. The roller bearing is equped with thin and rollers (roller diameter D≤5mm, L / D≥2.5, L is the roller length) The radial structure is compact. When the inner diameter and load capacity are the same as other types of bearings, the outer diameter is the smallest. It is especially suitable for the support structure with limited radial installation size.

According to the different ocns, the bearing or roller and cage aembly without inner ring can be selected. At this time, the surface of the journal matching the bearing and the surface of the housing hole are directly used as the inner and outer rolling surfaces of the bearing to ensure the load capacity and running performance. The same as the bearing with ring, the hardne of the surface of the raceway of the shaft or the housing hole, the hining accuracy and the surface quality should be similar to the raceway of the bearing ring. This type of bearing can only bear radial load.

Type

In addition to the bearings listed in the catalog, it can be used for general engineering bearings, such as: open drawn outer ring roller bearings (1), closed drawn outer ring roller bearings (2), inner ring roller bearings (3) and roller bearings with inner ring / roller bearings without inner ring (4), full roller bearings with and without cage (5) Our company can also supply various types of roller bearings, 1. cage aembly; 2. roller bearings without ribs; 3. S-aligning; 4. Combined roller / ball bearings 5. Combined roller / thrust ball bearings 6. Combined roller / cylindrical roller thrust bearings.

Compared

1. The friction coefficient of rolling bearings is smaller than that of sliding bearings, and the nsmiion efficiency is high. The friction coefficient of general sliding bearings is 0.08-0.12, while the friction coefficient of rolling bearings is only 0.001-0.005;

2. Rolling bearings have been standardized, serialized and generalized, suitable for ma production and supply, and are very convenient to use and maintain;

3. Rolling bearings are made of bearing steel and have undergone heat treatment. Therefore, rolling bearings not only have high mechanical properties and service life, but also save expensive nonferrous metals used in the manufacture of sliding bearings;

4. The internal clearance of the rolling bearing is small, and the hining accuracy of each part is high, therefore, the running accuracy is high. At the same time, the rigidity of the bearing can be increased by preloading. This is very ant for precision hinery;

5. Some rolling bearings can bear radial load and axial load at the same time, therefore, the structure of the bearing support can be simplified;

6. Due to the high efficiency of the rolling bearing nsmiion and le heat generation, the consumption of lubricating oil can be reduced, and lubrication and maintenance are relatively simple

7. Rolling bearings can be easily applied to shafts in any orientation in space.

Precaution

The bearing has a large load-bearing capacity and is suitable for supporting structures with limited installation dimensions.

The surface of the journal is hardened as a rolling surface, and the bearing is inserted into the seat hole by pre-fitting. There is no need to axially position it. Bearings should be filled with a proper amount of grease before installation. Normally, ar aembly, there is no need to relubricate. BK type bearings are used for the support of the journal without the protruding end. The end face is closed to seal and can withstand small axial movement.

The roller bearing is equped with thin and rollers (the length of the roller is 3 to 10 times the diameter, and the diameter is generally not more than 5mm), so the radial structure is compact, and its inner diameter size and load capacity are the same as other types of bearings. The smallest diameter, especially suitable for the support structure with limited radial installation size. roller bearings should be combined with bearing rings and applications depending on the application ocns, hining accuracy and surface quality. The roller bearing is a bearing unit composed of a radial roller bearing and a thrust bearing component.