Types of Full Complement Cylindrical Roller Bearings, Causes of Damage and Countermeasures

brandon smith September 19, 2022 \ Complement, full, Full Complement

Full complement cylindrical roller bearings are designed to withstand heavy loads. Under the same width, this kind of bearing has extremely high bearing capacity compared with the traditional bearing with cage. The radial section is small, which can save space, but the speed is relatively low. In order to make the bearing work normally, in the case of continuous operation, the bearing must bear a certain minimum load, that is, C/P<25. Otherwise, wear will be aggravate due to insufficient lubrication and high-speed operation. All multi-row cylindrical roller bearings have a lubrication groove and lubrication holes in the outer ring.

Full Complement Cylindrical Roller Bearing Type

1. It has two inner rings. The two inner rings are connect by a clamping ring and cannot be separate. The outer ring has a middle rib, which can bear bidirectional axial load and is use as a positioning bearing. Due to the large distance between the two rows of rollers, it can also withstand overturning moments. There are two retaining grooves on the surface of the outer ring, which can be position axially.

This type of bearing is equippe with contact sealing rings on both sides and lithium base grease inside, and the operating temperature is limit to -40℃～+80℃. Under certain conditions, this type of bearing does not need maintenance, but when there is water vapor or pollution during operation, and often at medium or high speed, it must be lubricate. In the case of oil lubrication, it is necessary to remove the sealing ring and clean the grease in the bearing. When oil lubrication is use, the running time is increase by 30%.

NNC/SL01 series full complement cylindrical roller bearings

NNC/SL01 series full complement cylindrical roller bearings are unseale bearings. The outer ring is integrally split and fix together by connecting lock pieces, so the outer ring cannot bear the axial load. The split outer ring is Exactly the same, each with a rib, which can be use for axial positioning in two directions. The inner ring has three ribs. The outer ring has oil grooves and three lubrication holes. This series of bearings is usually oil lubricate.

NNCL/SL02 series full complement cylindrical roller bearings

NNCL/SL02 series full complement cylindrical roller bearings are unseale bearings with no ribs on the outer ring, with oil grooves and three lubrication holes. The inner ring has three ribs. A fixed ring is install in the center of the outer ring between the two rows of rollers, which can prevent the rollers from falling out and keep the bearing as a whole. This series of bearings can allow a certain axial displacement between the shaft and the bearing seat to occur in the bearing. Because it can be use as a floating end bearing.

NCF…V/SL18 full complement cylindrical roller bearings

NCF…V/SL18 full complement cylindrical roller bearing, the outer ring has a single rib, and there is a lock ring on the side without a rib, which can be use for one-way positioning of the shaft, and the axial clearance “S” inside the bearing guarantees Axial positioning displacement of the crankshaft relative to the bearing housing.

NJ…V/SL19 full complement cylindrical roller bearings

NJ…V/SL19 type full complement cylindrical roller bearing is use for extremely heavy load and low speed occasions. It has a self-locking roller set. Even if the inner ring is remove, the rollers will not be scattere. Therefore, this type of bearing is easy to install and disassemble. Can bear one-way axial load for one-way positioning.

The dimensional tolerances and geometrical deviations of full complement cylindrical roller bearings should comply with GB/T307.1-94 (ISO492-1994) P0 tolerance level, and the normal original radial clearance CO, can also be require to have C2 to C4 original radial clearance Clearance bearings. However, the corresponding suffix should be add after the bearing code when ordering. Rubber and plastic screw extruders generally use C3 group clearance.

For the fit tolerance, please refer to the selection principle of bearing housing tolerance and the selection principle of shaft tolerance limit. Bearings are allow to bear a certain axial load. Adequate lubrication is a prerequisite for bearing axial loads.

The rib of one-way locating bearings and locating bearings that bear the axial load must be fully support. Installation and disassembly, when installing or disassembling cylindrical roller bearings, special attention must be pay to the fact that the installation or disassembly force cannot be directly transmitt through the cylindrical roller and the ring rib.

Dimensional Tolerances for Full Complement Cylindrical Roller Bearings

However, the corresponding suffix should be add after the bearing code when ordering. Rubber and plastic screw extruders generally use C3 group clearance. [1] For the fit tolerance, please refer to the selection principle of bearing housing tolerance and the selection principle of shaft tolerance limit.

Bearings are allow to bear a certain axial load. Adequate lubrication is a prerequisite for bearing axial loads. The rib of one-way locating bearings and locating bearings that bear the axial load must be fully support.

Installation and disassembly, when installing or disassembling cylindrical roller bearings, special attention must be paid to the fact that the installation or disassembly force cannot be directly transmitt through the cylindrical roller and the ring rib.

Causes and Countermeasures of Damage of NSK Full Complement Cylindrical Roller Bearings

Individually, with the correct use of full complement cylindrical roller bearings, it is possible to achieve fatigue life. However, if there is an accidental early injury, it cannot be reuse. Unlike fatigue life, this early damage is call a failure or accident. Most of them are cause by poor consideration of installation, utilization, and lubrication, foreign matter intruding from the outside, or insufficient research on shafts and bearing housings.

Injury conditions of full complement cylindrical roller bearings, such as scratches on the ring ribs of the roller bearings, may be cause by insufficient lubricant, unsuitable grades, defects in the oil supply and discharge structure, intrusion of foreign objects, errors in the nsk bearing installation or shafts. The deflection is too large, which may also be cause by a combination of the above causes.

Therefore, it is difficult to know the real cause of the damage only by looking at the bearing damage. ina bearing bearings have limited tolerances. They are particularly suitable for bearing arrangements that require very high guiding accuracy and speed capability. They are particularly suitable for bearing arrangements of shafts in machine tools.

The iko bearing has the advantages of higher rated load, lower noise, greatly reducing the warranty cost, and increasing the machine running time. Accurate identification, if this kind of stencil is touch by hand, there is no touch, but the presence of the stencil can be felt by lightly touching the stencil with a fingernail.

However

if you fully understand the machine, working conditions and peripheral structure of the bearing, clarify the situation before and after the failure, and then analyze the damage of the bearing and various related causes, it is possible to avoid similar failures again. There are representative bearing damage causes and countermeasures.

Even the most advance manufacturing techniques are use to process the complete machine of full complement cylindrical roller bearings. For skf bearings, refer to nsk bearing standards and SKF bearing standards to see that the standards for imported rolling bearings are universal. Nsk bearings have low starting friction and small difference in sliding friction control.

They are standardized and standardized internationally, and they have good interchangeability and can be use interchangeably between different brands. See how its reading changes with preload. The preload method has its downsides and is well known. Its working name always has the dial indicator against the proper part of the bearing end face or shaft.

1. Mechanical damage

In severe cases, metal peeling occurs on the contact surface and there is a large area of chaotic scratches; in individual cases, the mechanical damage of nsk bearings means that the alloy surface of the bearing bush shows different levels of groove marks. The main cause of the mechanical damage of the bearing due to the coexistence of contact surface damage and ablation phenomenon is that it is difficult to form an oil film or the oil film is seriously damage on the surface of full complement cylindrical roller bearings.

2. Bearing cavitation

The nominal layer produces plastic deformation and cold work hardening, and the full complement cylindrical roller bearing is under the repeated action of the cylinder pressure impact load). The deformation capacity is lost locally, and the lines gradually form and expan all the time. Then, as the wear debris falls off, the loaded nominal layer forms holes. When the individual bearing bushes are cavitated, pits appear first, and then the pits gradually expand and cause cracks at the interface of the alloy layer.

The cracks expand along the parallel direction of the interface until they peel off. The important cause of cavitation in nsk bearings is that the sudden change of the cross-section of structural factors such as oil grooves and oil holes causes the oil flow to be strongly chaotic, and bubbles are forme in the chaotic vacuum area of the oil flow. Cavitation is produce in the high load area of the bearing, such as the lower bearing pad of the crankshaft main bearing.

First of all, the structural design is reasonable and progressive, so that the bearing life will be longer. The manufacture of bearings must go through multiple processing processes such as casting, heat treatment, turning, grinding and assembly. The fairness, progress and firmness of each processing technology will also affect the life of the bearing.

Among them

the heat treatment and grinding processes that affect the quality of the finished bearing are often more directly related to the effectiveness of the bearing. In recent years, the research on the nominal metamorphic layer of the bearing work shows that the grinding process is closely related to the nominal quality of the bearing.

The metallurgical quality of the full complement cylindrical roller bearing material has been an important factor affecting the early effectiveness of nsk bearings. With the advancement of metallurgical technology (such as vacuum degassing of bearing steel, etc.), the quality of raw materials has been improve.

The proportion of raw material quality factor in the effective analysis of full complement cylindrical roller bearings has dropped significantly, but it is still one of the important factors affecting the effectiveness of nsk bearings. Whether the material is appropriate is still a factor that must be consider in the effective analysis of the bearing.

The important task of the effective analysis of the full complement cylindrical roller bearing is to find out the important factors that cause the bearing to become effective based on a large amount of background information, analysis data and the effective situation, so as to propose improvement measures in a targeted manner to extend the full complement cylindrical roller bearing. the service period, to avoid the sudden early entry into force of the nsk bearing.