Product Description:
How Many Information of Cylindrical Roller Bearings do You Learn More? Our this artical will make you in clear.
The rolling body is a centripetal rolling bearing with cylindrical rollers. The internal structure of cylindrical roller bearings adopts rollers arranged in parallel, with spacer keepers or isolation blocks between the rollers, which can prevent the tilting of the rollers or mutual friction between the rollers, effectively preventing the increase of rotating torque.
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Name
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Cylindrical Roller bearings
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Function of bearings
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Large and medium-sized electric motors, rolling stock
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Type
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roller bearings
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Precision
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P0, P6, P4, P2
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Introduction
Cylindrical roller bearings are line contact bearings with raceways. Large load capacity, mainly bear radial load. Rolling body and ring edge friction is small, suitable for high-speed rotation. According to the ring with or without edge, can be divided into NU, NJ, NUP, N, NF and other single row cylindrical roller bearings, and NNU, NN and other double row cylindrical roller bearings. The bearing is the structure of inner ring and outer ring can be separated.
Cylindrical roller bearings with inner or outer rings without retaining edges can be used as free-end bearings because the inner and outer rings can be moved relative to each other in the axial direction. Cylindrical roller bearings with double retaining edges on one side of the inner and outer rings and a single retaining edge on the other side of the collar can withstand a certain degree of axial load in one direction. Generally use steel plate stamping cage, or copper alloy turning solid cage. However, there is also a part of the use of polyamide forming cage.
Characteristics
1. Roller and raceway for line contact or repair under the line contact, radial bearing capacity is large, suitable for bearing heavy loads and shock loads. 2.
2. small friction coefficient, suitable for high speed, limit speed close to deep groove ball bearings.
3. N-type and NU-type can be moved axially, can adapt to the relative position of the shaft and shell due to thermal expansion or installation errors caused by the change, can be used as a free-end support.
4. the processing requirements of the shaft or seat hole is high, bearing installation of the outer ring axis of the relative skew should be strictly controlled, so as not to cause contact stress concentration.
5. inner or outer ring can be separated, easy to install and dismantle.
Product characteristics
Cylindrical roller and raceway is line contact, radial load capacity. It is suitable for bearing heavy loads and shock loads as well as high speed rotation.
Cylindrical roller bearing raceways and rolling elements are geometrically shaped. After improving the design, it has high load carrying capacity, the new structural design of the retaining edge and roller end face not only improves the axial bearing capacity, but also improves the lubrication conditions in the contact area between the roller end face and the retaining edge, which improves the performance of the bearings.
Structure
1.outer ring without stopping edge N0000 type and inner ring without stopping edge NU0000 type, cylindrical roller bearings such bearings can accept larger radial load, high limit speed, not bound axis or shell of the axial displacement, can not accept the axial load.
2. inner and outer ring are with the edge of the cylindrical roller bearings NJ0000 type, NF0000 type bearings can bind the shaft or shell of a direction of axial displacement, and can accept a smaller unidirectional axial load. NU0000 + HJ0000 type, NJ0000 + HJ0000 type, NUP0000 type bearings, can be imported in the field of axial clearance bearings bind the shaft or shell of the two direction of axial displacement, and can accept a larger radial load, high limiting speed, not bind the shaft or shell of axial displacement, can not accept axial load. The axial displacement, and can accept small bi-directional axial load .
Cylindrical Roller Bearings Category
Cylindrical roller bearings are split bearings, which are very easy to mount and dismount. Cylindrical roller bearings can withstand large radial loads and are suitable for use at high speeds.
These bearings allow a small angular error (tilt) of only 2′~4′ between the axis of the inner ring and the axis of the outer ring. Therefore, the shaft and housing of the relatively high machining accuracy or else, easy in the raceway contact parts of the uneven load or stress concentration. But the roller or raceway contact bus can reduce the occurrence of stress concentration after correction.
Cylindrical roller bearings according to the number of different columns of mounted rolling elements, can be divided into single row, double row and multi-row cylindrical roller bearings and other different structures. Different structure bearings are also manifested in the design of the position of the retaining edge. Among the commonly used cylindrical roller bearings have the following forms.
Single row cylindrical roller bearings: single row cylindrical roller bearings are separable bearings, easy to install and dismantle, both rings can be used with tight fit, modified roller and raceway between the contact line can reduce stress concentration.
Double row cylindrical roller bearings: double row cylindrical roller bearings belong to the travelling bearings, its separability makes the mounting and dismounting very convenient. Both rings can be used tight fit. Double row cylindrical roller bearings hardly allow tilting angle.
Single row bearings
N, NU type
N-type bearings have no retaining edges on the outer ring and retaining edges on both sides of the inner ring. Can allow the shaft relative to the bearing seat between the displacement in the axial direction in both directions.NU type bearing outer ring on both sides of the retaining edge, the inner ring has no retaining edge. It can also allow the displacement of the shaft relative to the housing in both axial directions. Therefore, this type of structure is suitable to be used as a swimming end bearing.
NJ, NF type
NJ type bearings have a retaining edge on both sides of the outer ring and a retaining edge on one side of the inner ring. Can withstand a certain amount of unidirectional axial load, NF-type outer ring single side of the retaining edge, the inner ring on both sides of the retaining edge. It can also bear a certain amount of unidirectional axial load. Therefore, this type of structure is suitable for use as a single-direction axial locating bearing.
NUP, NFP type
NUP type bearings have a retaining edge on both sides of the outer ring, a single (fixed) retaining edge on one side of the inner ring, and a separable flat retaining ring on the other side. It can bear a certain amount of bi-directional axial load.
NFP-type bearings have a single (fixed) retaining edge on one side of the outer ring, a separable flat retaining ring on the other side, and retaining edges on both sides of the inner ring. Can also withstand a certain amount of bi-directional axial load. These bearings can limit the displacement of the shaft relative to the housing in both axial directions. Therefore, they are suitable for use as fixed-end bearings.
NH (NJ+HJ) type
NH type bearings are a combination of NJ type bearings and HJ type tilting rings. Since the inner ring of NUP type bearings is shorter and the flat retaining ring is not fixed, it is not convenient to use, while NH type bearings can utilise the whole width of the inner ring of NJ type bearings to maintain a closer fit with the shaft. And NH type bearings are more convenient in mounting and dismounting.
NH type bearings can limit the displacement of the shaft relative to the housing in both axial directions. Therefore, they are suitable for use as fixed-end bearings.
Double row bearings
Double row cylindrical roller bearings have cylindrical bore and conical bore (bearing rear code plus K) two kinds of structure. These bearings have the advantages of compact structure, high rigidity, high load carrying capacity, small deformation after load, especially suitable for machine tool spindle support. Conical bore can also play a role in micro-adjustment clearance, and can simplify the structure of the positioning device, easy to install and dismantle. Commonly used double row cylindrical roller bearings have the following forms.
NN, NNU type
NN type bearing outer ring without edge, inner ring on both sides of the edge in the middle of the edge. Can allow the shaft relative to the bearing housing in the axial direction between the two directions of displacement.
The outer ring of NNU type bearings has retaining edges on both sides and a centre retaining edge in the middle, while the inner ring has no retaining edges. It can allow the axial displacement of the shaft relative to the housing in both directions. Therefore, this type of structure is suitable for travelling end bearings. The cage of this type of bearing is mostly made of solid cage.
NNF type
NNF type bearings are double rows of full complement cylindrical roller bearings, bearings by a band in the edge of the outer ring, two have double edge of the inner ring structure type. The rollers are guided by the retaining edge of the inner ring, and the two inner rings are fixed together with fastening rings. This structure can not only withstand a large radial load and axial load, but also can withstand tilting moment, therefore, commonly used as a fixed-end bearing.
NNF-type bearings are sealed with contact seals on both sides. The bearings are filled with grease, which has an operating temperature of -50°C to +110°C. However, due to the limitations of the sealing material, the operating temperature of the bearings is limited to -40°C to +80°C. In good operating conditions, the bearings can be used for a wide range of applications. Under good working conditions, NNF bearings with seals do not require maintenance. If the bearings are exposed to water vapour or pollution for a long period of time and are operated at medium or high speeds, the bearings can be supplemented with lubrication through lubricating oil grooves and lubricating oil holes on the outer ring.
Four rows of bearings
Four-row cylindrical roller bearings are mainly used in cold and hot rolling mills, billet openers and other rolling mill machinery. The bearings are of separated structure, the bearing rings and rolling body assemblies can be easily separated, so the bearings are easy to be cleaned, inspected, or mounted and dismounted.
FC type
FC type bearings are composed of two outer rings and one inner ring, each outer ring has a retaining edge on both sides and a middle retaining edge in the middle, and the inner ring has no retaining edge.
FCD type
FCD type bearings are actually a combination of two NN type bearings.
FC and FCD type bearings allow axial displacement in both directions between the shaft and the housing. Therefore, this type of structure is suitable for use as a travelling end bearing. The cage of this type of bearing is mostly made of turned solid 13:58 .
Accuracy class
Cylindrical roller bearings can be classified according to the accuracy class PO,P6,P5,P4,P2. The accuracy classes are sorted from low to high.
Cylindrical roller bearing radial clearance adjustment method
Commonly used methods to adjust the radial clearance of full complement cylindrical roller bearings are as follows.
1, for cylindrical and elliptical shingles side clearance can be adjusted by manual research and scraping or bearing centre parting surface with pad turning and then repair scraping.
2, for cylindrical and oval shingles top clearance can be used to manually scrape or when the situation permits the bearing in the part of the surface padding method of adjustment.
3, for multi-oil wedge fixed axial tile, in principle, does not allow scraping and adjustment of axial tile clearance, clearance should be replaced with a new tile.
4, for multi-oil wedge tiltable tile, not allowed to scrape the block, the gap is not appropriate should be replaced because of the tile block. Adjustable thickness of the tile, can be adjusted through the tile behind the adjusting block under the stainless steel pad, or thinning the thickness of the adjusting block method to adjust the amount of tile. Attention to the multi-oil wedge tilting type shaft tile, the thickness error between the same group of tile blocks should be less than 0.01mm.
APPLICATIONS
Large and medium-sized electric motors, rolling stock, machine tool spindles, internal combustion engines, generators, gas turbines, reduction gearboxes, rolling mills, vibrating screens, and lifting and transport machinery.
Attention
Vibration
In ordinary use, vibration is quite sensitive to bearing damage, spalling, indentation, corrosion, cracks, wear, etc. will be reflected in the bearing vibration measurement. Therefore, the magnitude of vibration can be measured by using special bearing vibration measuring instruments (frequency analysers, etc.), and the specifics of the abnormality can be deduced from the frequency distribution. The measured value varies depending on the conditions of use of the bearing or the location of the sensor installation, etc., so it is necessary to analyse and compare the measured value of each machine beforehand to determine the criteria for judgement.
Folding Temperature
High temperatures are often used to indicate that a cylindrical roller bearing is in an abnormal condition. High temperatures are also detrimental to the bearing lubricant. Sometimes bearing overheating can be attributed to the bearing lubricant. If a bearing is rotated continuously for a long period of time at temperatures in excess of 125°C, bearing life will be reduced. Causes of high bearing temperatures include: insufficient or excessive lubrication, impurities in the bearing raceways, high limiting speeds, and long-term overloading of the bearing.
Maintenance
Disassembly
The disassembly of bearings is carried out for regular maintenance and bearing replacement. After disassembly, if the bearings continue to be used, or if it is necessary to check the status of the bearings, the disassembly should be carried out with the same care as when they are installed. Be careful not to damage the bearing parts, especially the disassembly of interference fit bearings, which are difficult to operate.
It is also very important to design and make dismantling tools according to the needs. When disassembling, according to the drawings to study the disassembly method, order, investigate the bearing with the conditions, in order to get the disassembly operation of the foolproof.
The outer ring of the disassembly of the outer ring of the interference fit, set up in advance in the shell of the circumference of the outer ring of the extrusion screw with a few screws, one side of the equal tightening of the screw, the side of the disassembly. These screw holes are usually covered with blind plugs, tapered roller bearings and other separating bearings, set up a few cuts in the shell blocking shoulder, use the pads, dismantle with a press, or gently tap to dismantle.
The inner ring can be disassembled most simply by pulling out with a press. At this point, be careful to allow the inner ring to withstand its pulling force. Further, the pull-out fixtures shown are also mostly used, and regardless of the type of fixture, it must be firmly seated on the side of the inner ring. For this reason, it is necessary to consider the size of the shaft shoulder, or study in the shoulder processing on the groove, in order to use the pulling tool.
The inner ring of large bearings is dismantled by means of oil pressure. Oil pressure is applied through the oil holes set in the bearing to make it easier to pull out. For bearings with a large width, the hydraulic method is used in conjunction with the pulling jig to dismantle the bearing.
Cylindrical roller bearings can be dismantled by induction heating. In a short period of time, local heating, so that the inner ring expansion after pulling method. The induction heating method is also used when a large number of inner rings of these bearings are to be mounted.
Cleaning
When the bearing is dismantled for inspection, the appearance of the bearing should be recorded by photography or other means. In addition, the amount of remaining lubricant should be confirmed and the lubricant should be sampled before cleaning the bearing.
a. Cleaning of bearings is divided into rough and fine washing, and a metal mesh frame can be placed at the bottom of the container used.
b, coarse washing, in the oil with brushes and so on to remove the grease or adhesion. At this time, if the bearings are rotated in the oil, it is noted that the rolling surface will be damaged due to foreign objects.
c. For fine washing, turn the bearing slowly in the oil, and do it carefully.
Usually use the cleaning agent for neutral water-free diesel oil or paraffin, according to the need to sometimes use warm lye and so on. No matter which cleaning agent is used, it should be filtered frequently to keep clean.
Immediately after cleaning, coat the bearings with anti-rust oil or anti-rust grease.
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