Product Description:
|
Name
|
needle roller bearings
|
Feature
|
the roller are thin and long
|
|
Insturction
|
Needle
|
Description
|
roller bearings with cylindrical rollers
|
Needle roller bearings (needle bearings) are roller bearings with cylindrical rollers, relative to their diameter, the rollers are both thin and long. These rollers are called needle rollers. Despite having a small cross-section, the bearing still has a high load bearing capacity, needle roller bearings are equipped with thin and long roller (roller diameter D ≤ 5mm, L / D ≥ 2.5, L for the roller length), so the radial structure is compact, its inner diameter size and load capacity and other types of bearings with the same, the smallest outside diameter, especially for radial mounting dimensions of the support structure is limited.
According to the use of different occasions, can choose no inner ring bearings or needle and cage assembly, at this time and bearing with the surface of the journal and shell hole surface directly as the bearing of the inner and outer rolling surface, in order to ensure the load capacity and running performance and have the same ring bearings, shaft or shell hole raceway surface hardness, machining accuracy and surface quality should be similar to the bearing ring raceway. This kind of bearing can only bear radial load.
Characteristics
Needle roller bearings equipped with thin and long roller (roller diameter D ≤ 5mm, L / D ≥ 2.5, L for the roller length), so the radial structure is compact, its inner diameter size and load capacity and other types of bearings with the same, the smallest outside diameter, especially suitable for radial mounting dimensions of the support results of the limitations. According to the use of different occasions, can choose no inner ring bearings or needle and cage assembly, at this time and bearing with the journal surface and shell hole surface directly as the bearing of the inner and outer rolling surface, in order to ensure the load capacity and running performance and have the same ring bearings, the shaft or shell hole raceway surface hardness, machining accuracy and surface quality should be similar to the bearing ring raceway. This kind of bearing can only bear radial load.
Types
In addition to the catalogue listed, can be used for general engineering bearings, such as: open stamped outer ring
Needle roller bearings
Needle roller bearings
Needle roller bearings (1), closed drawn cup needle roller bearings (2), needle roller bearings with inner ring (3) and needle roller bearings without inner ring/without inner ring/without cage needle roller bearings (4), with cage and without cage filled needle roller bearings (5) SKF can also supply a variety of types of needle roller bearings, 1, needle roller cage assemblies 2, needle roller bearings without cage, 3, self-aligning 4, combined needle roller/ball bearings 5, combined Needle roller/thrust ball bearings6, combined needle roller/cylindrical roller thrust bearings
STO outer ring without retaining edge, with inner ring support roller
RNA22.... .2RS Double-sided seal, without inner ring support roller
NA22...2RS ...2RS double-sided sealing, with inner ring support roller
NATR
NATR.... ...PP flat ring axially guided bearing track rollers
Needle roller bearings
Needle roller bearings
NATV
NATV.... .PP axial guidance track rollers with flat Retaining ring, full complement needle roller type
NUTR rolling element guide bearing track rollers, full complement roller type
CRY Axially guided bearing track rollers with flat retaining rings in inch sizes
Stamped outer ring
Drawn cup needle roller bearings are needle roller bearings with a thin, drawn outer ring. Their main feature is that they have a low cross-section height and a high load carrying capacity. They are mainly used in compact, inexpensive bearing configurations where the bore of the bearing box cannot be used as a raceway for the needle roller cage assembly. Bearings and bearing boxes must be installed in an interference fit. If the axial locating function of the box shoulder, stop ring, etc. can be omitted, then the bearing box bore can be made very simple and economical.
Drawn cup needle roller bearings mounted on the shaft end are available in double-sided open type and single-sided closed type. The base end face of the closed stamping outer ring can withstand a small axial guiding force.
Drawn cup needle roller bearings generally do not have an inner ring. In the journal can not be hardened and grinding occasions, can be used in the table listed in the inner ring.
The hardened steel outer ring of a drawn cup needle roller bearing is inseparable from the needle roller cage assembly. The free space for storing lubricant allows for longer refill intervals between lubrications. The bearings are generally of single-row design. The exceptions are the wider sizes of bearings in the 1522, 1622, 2030, 2538 and 3038 series, which are fitted with two needle roller cage assemblies. The outer ring of the bearing has a lubricating oil hole. According to user requirements, all single row drawn cup needle roller bearings with shaft diameters greater than or equal to 7 mm can be equipped with an outer ring with lubrication holes (designation suffix AS1).
Drawn cup needle roller bearings with oil seals
Where oil seals cannot be fitted due to space constraints, drawn cup needle roller bearings with oil seals are available with open or closed ends (3 to 5). These bearings are equipped with friction type oil seals made of polyurethane or synthetic rubber, filled with lithium grease with good corrosion protection, and are suitable for operating temperatures from -20 to +100°C. The inner ring of these bearings has a larger diameter than the inner ring.
The inner ring of the bearings with oil seals is 1mm wider than the outer ring, which enables the bearings to ensure that the oil seals work well and prevent the bearings from being contaminated when there is a slight displacement of the shaft relative to the bearing box. The inner ring of the bearing also has lubrication holes, which can be supplemented by the outer ring or the inner ring according to the needs of the bearing configuration.
Classification
1. radial needle roller and cage assemblies
2. NA, NKI type needle roller bearings
3. Needle roller bearings without inner ring, type RNA, NK
4. Drawn cup needle roller bearings type HK
5. BK Type Drawn Cup Needle Roller Bearings
English type
Metric series: HK, BK, F, FH, FY, MF, MFH, MFY; TA...Z, TLA...Z, TAM, TLAM, YT, YTL.
Inch Series:SCE, BCE, SCH, BCH, SN, B, BH, M, MH,;BA.... .Z, BHA... .Z, BAM, BHAM, YB, YBH. Example: HK XX YY type Inner cut circle diameter XX Height YY
RS------ for one seal with metric system
2RS----- is two seals with metric system.
P------- is one seal with imperial system.
PP------ is two seals with imperial system.
ASI/OH - for oil hole HK, BA, TA...Z - perforated type drawn cup needle roller bearings BK, TAM, TLAM - sealed type drawn cup needle roller bearings
F--Piercing type drawn cup full complement needle roller bearings
FY、YT--Piercing type stamping outer ring full complement needle roller bearings (grease limit)
FH、YTL--Perforated type stamping outer ring full complement needle roller bearings (heavy series)
MF--Sealed type drawn cup full complement needle roller bearings
MFH--Sealed Type Drawn Cup Full Compliment Needle Roller Bearings
SCE--Perforated type drawn cup needle roller bearings
BCE--Sealed type drawn cup needle roller bearings
SCH--Piercing type drawn cup needle roller bearings
BCH--Sealed type drawn cup needle roller bearings
SN--Piercing type drawn cup full complement needle roller bearings
B--Piercing type stamping outer ring full complement needle roller bearings
BH--Piercing type Drawn Cup Full Compliment Needle Roller Bearing(Heavy Series)
M--Sealed type drawn cup full complement needle roller bearings
MH--Sealed type drawn cup full complement needle roller bearings (heavy series)
"physical collusion", a form of fraudulent sexual activity whereby the victim is caught in a trap
Solid ring needle roller bearings consist of one or two rings and a needle roller set with a cage. Depending on the application, they can be classified as bearings with or without inner rings. Therefore, solid collar needle roller bearings can meet the requirements of light weight, small space occupation and high power transmission. Solid sleeve needle roller bearings have smaller volume and higher load carrying capacity.
Structure type
Outer ring double block edge (or double lock ring) with cage needle roller bearings NA, NKI type
Inner and outer rings (with locking ring, full set of needle rollers and cage) can be mounted separately, with high permissible speed, in single and double rows.
If the shaft cannot be used as a raceway, i.e., if it is impossible or uneconomical to harden the shaft by grinding, such needle roller bearings with inner rings can be used.
Characteristics
NA, NKI type bearings without inner ring is RNA, NK type needle roller bearings.
This kind of bearing without inner ring, suitable for radial mounting size is limited by the support structure, and bearing with the matching journal directly as the rolling surface. As the raceway surface of the shaft, must be hardened hardware and grinding, and only its processing to the appropriate size and shape accuracy, the whole set of needle roller bearings can be higher life and running accuracy. At the same time, since there is no inner ring, the diameter of the shaft can be appropriately enlarged, thus also increasing the rigidity.
Combined type
Combined needle roller bearing is a bearing unit combining centripetal needle roller bearings and thrust bearings, which has compact structure, small volume, high rotational accuracy, and can bear a certain axial load at the same time of bearing high radial load. And the product structure of various forms, wide adaptability, easy to install.
Combined needle roller bearings are widely used in machine tools, metallurgical machinery, textile machinery and printing machinery and other mechanical equipment, and can make the mechanical system design is very compact and smart.
Thrust type
Thrust bearings consist of a thrust cage assembly with needle or cylindrical rollers or balls and a thrust washer. The needle and cylindrical rollers are retained and guided by the thrust cage. When used in conjunction with different series of DF thrust bearing washers, many different combinations of bearing configurations are possible. Due to the choice of high-precision cylindrical rollers (needle rollers) with increased contact lengths, high load carrying capacity and high stiffness can be achieved in a very small space with this bearing. Another advantage is that washers can be omitted if the surfaces of neighbouring parts are suitable for raceway surfaces, which makes for a compact design, and the cylindrical surfaces of the needles and cylindrical rollers used in DF axial needle roller bearings and axial cylindrical roller bearings are modified surfaces, which reduces the edge stresses and improves the service life.
Mounting
The mounting of a full complement needle roller bearing is usually carried out using an auxiliary sleeve. In this case, the auxiliary roller or auxiliary sleeve holds the needle roller from falling out, the journal lifts up the needle roller by its own chamfering angle, and the auxiliary roller or auxiliary sleeve slowly withdraws as the needle roller bearing moves inward on the journal until it is mounted in the working position.
Auxiliary roller, auxiliary sleeve should be smaller than the shaft diameter of the outer diameter of 0.1-0.3mm. installation, the first bearing outer ring of the inner surface coated with grease, against the inner surface of the tightly affixed to the needle roller (into the last needle roller should be left with a gap), and then instead of the journal or the bearing inner ring of the auxiliary rollers or auxiliary sleeve pushed into the hole of the outer ring, and to make its end face to the installation of the shaft end face or has been installed in the axis of the bearing inner ring end face. Then push the auxiliary roller or auxiliary sleeve in place of the journal or inner ring into the bore of the outer ring and align its end face with the end face of the mounting shaft or the end face of the inner ring already mounted on the shaft, and then apply pressure by tapping with a press or hand hammer.
Needle roller bearings can also be installed in this way, that is, the outer diameter of the auxiliary sleeve coated with a thin layer of lubricating oil, set into the outer ring of the bearing, so that the auxiliary sleeve and the outer ring of the bearing constitutes a ring hole, and then in the ring hole in the installation of needle rollers. After loading the needle roller, the auxiliary sleeve can be pushed out with the working shaft.
For no inner ring or no outer ring needle roller bearings, in the installation, can be the first shaft or shell hole rolling surface coated with a thin layer of grease, and the needle roller in order to tightly pasted on the installation parts of the grease. Paste put the last needle roller should leave a gap, the size of the gap in the circumference of the needle roller bearing to 0.5mm is appropriate. Can't put the last needle roller hard extrusion mounted, or less than a needle roller, because hard extrusion mounted, the bearing will be stuck can't rotate; Less mounted, the clearance is too large, easy to cause the bearing running needle roller twisting and breaking. For only stamping outer ring needle roller bearings, due to the outer ring wall is very thin, don't use hand hammer to knock installation, should use the press to press in. Because when hammering, the pressure is not uniform, it is easy to make the outer ring of needle roller bearings produce local deformation.
Comparison
1. The friction coefficient of rolling bearings is smaller than that of plain bearings, and the transmission efficiency is high. General sliding bearing friction coefficient is 0.08-0.12, and rolling bearing friction coefficient is only 0.001-0.005.
2. Rolling bearings have been standardised, serialised, generalised, suitable for mass production and supply, use and maintenance is very convenient.
3. rolling bearing with bearing steel manufacturing, and after heat treatment, therefore, rolling bearing not only has high mechanical properties and long service life, and can save the manufacture of sliding bearings used in the more expensive non-ferrous metals.
4. Rolling bearing internal clearance is very small, the machining precision of each part is high, therefore, the running precision is high. At the same time, can make the bearing rigidity increase by preloading method. This is very important for precision machinery.
5. Some rolling bearings can bear radial load and axial load at the same time, therefore, can simplify the structure of bearing support.
6. Due to the rolling bearing transmission efficiency, less heat, therefore, can reduce the consumption of lubricating oil, lubrication and maintenance is more trouble-free.
7. Rolling bearings can be conveniently applied to the shaft in any position in space.
Attention
Needle roller bearings have large load carrying capacity and are suitable for supporting structures with restricted mounting dimensions. The surface of the journal is hardened as the rolling surface, and the bearing is fitted into the seat hole with a press fit, so it is not necessary to locate it in the axial direction.
Bearing should be injected with appropriate amount of grease before installation, usually, no need to lubricate after assembly BK type bearings are used in the support of the journal without extending end, the end face is closed to play the role of sealing, and can withstand a small axial movement.
Causes of damage
Generally speaking, 33.3% of needle roller bearings are damaged due to fatigue damage, 33.3% are damaged due to poor lubrication, and another 33.3% are damaged due to contaminants entering the bearings or improper disposal of equipment.
Dust
Clean the bearings and the surrounding environment, the naked eye can not see the fine dust are bearings of powerful killer, it can increase the bearing wear, vibration and noise.
Stamping
In the use of equipment to form a strong stamping, it is very likely to lead to needle roller bearing damage or the use of hammers to directly hit the bearing, through the tumbler to transfer the pressure and so on.
Influence of non-professional tool installation
The use of suitable and accurate equipment should be used as much as possible, and the use of cloth and short fibres should be avoided. Needle roller bearing no matter in the laboratory test or in practice use, can obviously see, in the same operating conditions of the appearance of the same needle roller bearing, the actual life of it has a big difference.
Disassembly method
Knocking method
Tapping force is generally added to the inner ring of the bearing, shielding machine room tapping force should not be added to the rolling body of the bearing and cage, this method is simple and easy to implement, but easy to damage the bearings, when the bearing is located at the end of the shaft, with less than the inner diameter of the bearing of the copper rod or other soft metal materials against the end of the shaft, the bearing of the lower part of the cushion block, gently knock with a hand hammer, you can dismantle. Application of this method should pay attention to the location of the cushion should be placed in the appropriate position, the point of gravity should be correct.
Hot dismantling method
Used to dismantle the tight fit bearing. The first will be heated to about 100 ℃ oil with oil pots poured in the bearing to be dismantled, to be bearing ring thermal expansion, you can use the pulling tool will be pulled out of the bearing.
Pushing method
Push the bearing with the press, work smoothly and reliably, without damage to the machine and bearing shielding machine room. Presses have manual push pressure, mechanical or hydraulic press push pressure.
Attention: the pressure point should be in the centre of the shaft, shall not be pressed off.
Pull out method
The use of special pulling tools, disassembly, as long as the rotation of the handle, the bearing will be slowly pulled out. When disassembling the outer ring of the bearing, the angle of the two feet of the pulling tool should be outwardly open; when disassembling the inner ring of the bearing, the two feet of the pulling tool should be inwardly, stuck on the end surface of the inner ring of the bearing.
Advantages and usability of needle roller bearings
Needle roller bearings are equipped with thin and long roller (roller length for the diameter of 3 ~ 10 times, the diameter is generally not more than 5mm), so the radial structure is compact, its inner diameter size and load capacity and other types of bearings the same, the smallest outside diameter, especially suitable for radial mounting dimensions of the support structure is limited. Needle roller bearings according to the use of different occasions, processing accuracy and surface quality should be combined with bearing collar, use. Needle roller bearings are bearing units combined with centripetal needle roller bearings and thrust bearing components.
#rahbearings #needlerollerbearings #chinabearings #ikoneedlerollerbearings #manufacturerbearings
