The cylindrical roller bearings (CRBs) manufactured by RKB are produced in many designs, dimensions and series, to withstand heavy radial loads and medium speeds, covering most of the requirements in a variety of standard and special industrial applications. All CRBs manufactured by RKB offers the highest load rating capacities, improved internal geometry, high quality materials and special heat treatments for superior performance.
RKB CRBs are available with cylindrical or tapered bore in single, double or multi row confi guration. Depending on application requirements, RKB Bainite Hardening Treatment (HB) and High Temperature Dimensional Stabilization (S) can be applied on bearing rings and rollers. The bearing dimensional and running accuracy conforms to ISO/ABMA/GOST specifi cations.
RKB offers a wide range of single row cylindrical roller bearing designs in normal or reinforced execution with increased performance in critical applications. Roller and raceway profi les are designed to attain optimized
stress distribution while minimizing the edge effect, especially under critical conditions.
The portfolio of RKB single row CRBs is fi nally enhanced by the high-capacity full complement bearings (cageless), which reach higher load carrying capacities within the same boundary dimensions.
RKB produces cylindrical roller bearings in various design styles, sizes and dimension series.
RKB heavy duty radial cylindrical roller bearings are designed to provide the highest possible radial capacity for the given cross section and to perform under heavy radial loads. These bearings incorporate improved internal proportions developed through computer assisted optimization studies, to make the maximum use of the total available cross-sectional area. The rollers have controlled contour to redistribute end stress concentration and provide more uniform distribution of the applied loads (suffix ZB). Their surface finishing maximizes lubricant film formation and optimizes rolling motion.
The standard ISO assortment of RKB production program includes single and double row bearings with a cage that can accommodate heavy radial loads and operation at high speeds.
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With a wide range of executions of double row cylindrical roller bearings (DRCRBs), RKB is able to fulfi ll any requirement in demanding applications such as large size gearboxes, machine tools, grinding mills and crushers.
To ensure superior performance, RKB double row cylindrical roller bearings are manufactured from high quality special steels, heat treated in optimized automatic lines.
With improved internal geometry and profi le, DRCRBs can withstand high radial loads within a narrow cross section.
RKB cylindrical roller bearings with four or six rows have low cross section, high load carrying capacity and stiffness, and are particularly used for metal rolling equipment in mills, where the equipment has been scaled down and jet loads remain high.
These bearings are only able to accommodate radial loads, therefore they are mounted together with deep groove or angular contact ball bearings or with taper roller bearings which take up the axial loads. The four-row cylindrical roller bearings are of separable design, which considerably simplifies mounting, maintenance and inspection.
RKB cylindrical roller bearings can tolerate moderate to high shaft speeds. The rollers and outer races are carefully matched to ensure the best load distribution.
Inner rings (designation L) are interchangeable with other assemblies (designation R). Moreover, RKB multi row bearings allow direct interchange with main premium competitor products.
RKB has a flexible manufacturing program of different styles (also special) and sizes for multi row bearings.
They have cylindrical bore and some sizes are also available with tapered bore as required by the application or by maintenance request.
The use of multi row cylindrical roller bearings in metal rolling mills exposes them to very heavy stresses, sometimes to impact loadings. The rings and rollers can be manufactured with very high quality case hardened carburizing alloy steels. Deep case depth and special heat treatment ensure superior size stability, fracture toughness and reliability.
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The tapered roller bearings (TRBs) manufactured by RKB are engineered to withstand combined radial and thrust loads. Available in a rich portfolio of designs and sizes, in standardized and non-standardized dimensional series, RKB tapered roller bearings can be in metric or inch measurements and represent the state of the art. Manufactured from high hardness materials, featuring unparalleled fatigue strength and resistance to wear, RKB TRBs provide excellent performance even under severe operating conditions.
RKB’s single row, matched pair, double and four-row tapered roller bearings are optimized to ensure increased load carrying capacities and high stiffness in special applications. RKB Bainite Hardening Treatment (HB) and High Temperature Dimensional Stabilization (S) can be applied on bearing rings and rollers.
RKB single row and matched pair tapered roller bearings (SRTRBs) are widely used in all industrial segments, in standard and critical applications. The tighter dimensional tolerances, obtained through an extremely high precision manufacturing technology, and the optimized inner geometry (E-Type class) make of such bearings a reliable solution to improve the performance of any machine.
Naturally, the matched pairs can be assembled according to the customer’s special needs (e.g. a given axial internal clearance). The bearing dimensional and running accuracy conforms to ISO/ABMA/GOST specifi cations.
RKB taper roller bearings have the rolling elements under the form of frustum of cone. They roll on tapered surface which, if extended, converges towards a single point on the bearing axis.
The rollers are guided tangentially by the cage and axially by the big rib of the inner ring, on which they have contact. As between rollers and raceways there is linear contact, they can take heavy radial loads. They can also take heavy axial or combined loads, depending on the contact angle caused by the tapered elements.
The contact angle is the one of the outer raceway generatrix.
The single row taper roller bearings are of separable design, which means the outer ring/cup and the inner ring/cone with rollers and cage assembly can be separately mounted. The two parts are interchangeable.
RKB taper roller bearings are manufactured both in standardized (metric and inch sizes) and in non-standardized constructive version.
The taper roller bearings can carry only single direction axial loads. Under pure radial loads, an axial force is induced within the bearings so that they cannot be used singly and a second bearing is required.
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RKB double row tapered roller bearings (DRTRBs) are produced in several confi gurations (TDO, TDOS, TDI, TDIS) to support combined forces and locate the shaft in both directions. Manufactured with a given axial clearance (BEP), DRTRBs can fully exploit their potential in a variety of industries and applications. In order to manufacture products with the highest possible resistance to fatigue and wear, RKB makes use of different bearing steel grades and special heat treatments. The bearing dimensional and running accuracy conforms to ISO/ABMA/GOST specifi cations.
RKB double row taper roller bearings can take up heavy loads and are stiff.
Suitable for combined radial and axial loads, they locate axially the shaft in both directions with the stated axial end play (also defined as BEP - Bench End Play) or given preload.
The basic styles are two-row converging TDI configuration and two-row diverging TDO configuration.
Rings and rollers are made of high chrome through hardening steels or case hardened carburizing alloy steels depending on the application.
Cages for RKB double row taper roller bearings are stamped pressed steel. A steel pin-type cage, which allows a larger complement of rollers for higher capacity, is also available.
This style of bearing set simplifies design and reduces the danger of bearing clearance changes due to axial shaft expansion.
It is important the definition of the proper internal play related to the application.
RKB bearings in TDI configuration have a double cone assembly and two single cups and they are generally supplied with a cup spacer.
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RKB four-row tapered roller bearings (FRTRB) are produced mainly in TQO and TQI confi guration, in open and sealed version. Supplied with the required axial internal clearance (BEP), they are mainly employed on work rolls of rolling mill applications.
The use of high quality raw materials, special heat treatments, and innovative sealing solutions are at the base of their higher operating reliability and longer service life expectancy. The bearing dimensional and running accuracy conforms to ISO/ABMA/GOST specifi cations.
RKB four-row taper roller bearings are installed as complete assemblies and take axial loads in addition to heavy radial loads, so that generally it is not requested separate thrust bearings in such arrangements.
They are commonly used in rolling mill applications.
For quick roll changes, the bearings have a loose fit on the roll necks, but there is the disadvantage that the inner rings wander on their seatings causing wear. To reduce these negative effects, RKB bearings have a helical groove in the bore and lubrication grooves in the side faces of the inner rings. These grooves enable lubricant to be supplied to the contact surfaces of the inner ring and seating.
Since wear and shock resistance under heavy rolling loads is a requirement for roll neck bearings, highest quality carburizing grade bearing alloy steels are normally used in RKB four-row taper roller bearings.
Besides, for large size bearings, pierced rollers and steel pin-type cage for maximum load ratings possible are applied.
The induced thrust resulting from radial loading is cancelled within the double cones and it eliminates excessive loads on clamping and spacing members.
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The ball bearings (BBs) manufactured by RKB come in many designs, dimensions and series. They are conceived to withstand combined loads and high speeds, covering most requirements in a number of standard and special industrial applications. All RKB BBs are made from high quality materials and special heat treatments for superior performance.
Available in single and double row confi guration, in open or sealed version, they are low-maintenance, which makes them an irreplaceable cost-effective solution in many cases.
For large size BBs, RKB can also apply Bainite Hardening Treatment (HB) and High Temperature Dimensional Stabilization (S) on rings and balls. The bearing dimensional and running accuracy conforms to ISO/ABMA/GOST specifi cations.
RKB offers a wide range of deep grove ball bearings (DGBBs) in single row design (open, sealed or shielded), with proven performance in many industrial fi elds. Having optimized internal geometry, they can operate at high speeds, sustaining radial and axial loads in both directions and generating low friction.
RKB DGBBs are engineered to successfully respond to the most demanding application requirements, in terms of high speeds, heavy loads and low noise. This is mainly due to the use of the best raw materials and manufacturing technology, that permit to deliver only premium deep groove ball bearings.
Non-separable, for operations at high speeds, of simple design and little maintenance, RKB deep groove ball bearings are the most versatile and popular bearings in rolling applications.
The internal designs are the Conrad assembly (the majority of the production) and the filling slot assembly (for special applications with cage or with full ball complement).
The single row deep groove ball bearings can take radial and double direction axial loads.
They have limited abilities to compensate for errors of misalignment. Because of the values, in order to avoid inadmissible high additional loads and noise increase as a result of complex relationships among several influencing factors, the permissible misalignments are considered those between 2 to 10 minutes of arc depending on the bearing series.
The basic design of RKB deep groove ball bearings is open type either with boundary metric dimensions in accordance with ISO 15:1988 or with inch dimensions as per American AFBMA specifications.
The version with a snap ring groove on the outer ring (suffix N) for the easy axial location in the housing is in accordance with ISO 464.
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RKB offers a wide range of deep grove ball bearings (DGBBs) in single row design (open, sealed or shielded), with proven performance in many industrial fi elds. Having optimized internal geometry, they can operate at high speeds, sustaining radial and axial loads in both directions and generating low friction.
RKB DGBBs are engineered to successfully respond to the most demanding application requirements, in terms of high speeds, heavy loads and low noise. This is mainly due to the use of the best raw materials and manufacturing technology, that permit to deliver only premium deep groove ball bearings.
RKB single angular contact ball bearings are designed to accommodate combined loads acting in radial and axial direction. They can take axial loads in one direction only.
When radially loaded, in the bearing occurs an axially acting load which has to be compensated. For this reason one bearing or paired bearings are mounted on each shaft end.
These bearings are not separable and their use at relatively high speed is allowed.
In the case of single row angular contact ball bearings the efforts between rings and rolling elements are transmitted at an angle to a plane perpendicular to the bearing axis. The value of this angle depends on the magnitude of the raceway radius, ball diameter and radial clearance in the bearing when the curvature centers of the raceway are in the same plane.
The main dimensions are in accordance with ISO/R 15. The values for the tolerance of the normal, P6 and P5 classes conform to ISO 492.
Internal axial clearance or preload is obtained only when the bearings are mounted in the assembly and depends on the location of the second bearing which assures the shaft axial guiding.
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The spherical roller bearings (SRBs) manufactured by RKB are engineered to withstand high radial forces and moderate axial forces acting in both directions. RKB SRBs can dynamically accommodate misalignments due to shaft bending. They are produced with cylindrical or tapered bore, in open or sealed execution. Depending on application requirements, RKB Bainite Hardening Treatment (HB) and High Temperature Dimensional Stabilization (S) can be applied on bearing rings and rollers. Moreover, as for dimensions, RKB spherical roller bearings are manufactured according to ISO/ABMA/GOST specifi cations. As a consequence, they are fully interchangeable with all the bearings that meet the relevant international standards.
The range of RKB spherical roller bearings covers most requirements of standard and special industrial applications, in severe and critical working conditions.
RKB offers a wide portfolio of open and sealed SRBs in all diameter and width series. While the narrow low-section bearings (e.g. 238 series) feature high speed capabilities as well as low weight and minimum space dimensions, the wide high-section bearings (e.g. 233 series) have higher load carrying capacities. All RKB SRBs put together experience in design with proven performance in all major industries.
RKB spherical roller bearings are self-aligning and consequently insensitive to the misalignment of the shaft relative to the housing and insensitive to shaft deflection or bending. The permissible value is up to 3.5° approximately depending on bearing series and size.
These bearings have two rows of rollers with sphered raceway in the outer ring and two inner ring raceways inclined at the proper angle to the bearing axis.
Used to operate in arduous conditions, leading in design, RKB spherical roller bearings can accommodate, in addition to high radial loads, axial loads acting in both directions.
RKB small and medium size spherical roller bearings are usually fitted with pressed steel cage or one-piece machined brass cage where the bearings have a central guide rib on the inner ring and symmetrical rollers with large dimensions for increased carrying capacity.
The bearings of normal design, with a central fixed rib, are fitted with machined brass or steel cage guided on the rollers or on the inner ring or outer ring raceway.
The main dimensions are in accordance with ISO 15.
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Tailor Made Solutions
Besides the main spherical roller bearing designs, RKB has developed new solutions according to specifi c application requirements. The special designs include SEALED SRBs, for smooth operation in contaminated environments, ROVSX type, expressly designed for vibratory equipment, WOR execution, suitable for gear output shaft of truck concrete mixers, and SPLIT bearings to make maintenance operations easier at hard-to-reach positions. If duly applied, these special designs are cost effective for the customer, since they allow increased bearing life expectancy and reduced machine downtime.
The spherical roller bearings (SRBs) manufactured by RKB are engineered to withstand high radial forces and moderate axial forces acting in both directions. RKB SRBs can dynamically accommodate misalignments due to shaft bending. They are produced with cylindrical or tapered bore, in open or sealed execution. Depending on application requirements, RKB Bainite Hardening Treatment (HB) and High Temperature Dimensional Stabilization (S) can be applied on bearing rings and rollers. Moreover, as for dimensions, RKB spherical roller bearings are manufactured according to ISO/ABMA/GOST specifi cations. As a consequence, they are fully interchangeable with all the bearings that meet the relevant international standards.
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The broad portfolio of single direction thrust bearings (SDTBs) engineered and produced by RKB offers cost-effective solutions for the most demanding industries.
SDTBs只能承受单向轴向载荷s, axially locating the shaft. Roller and raceway profi les are designed and manufactured to reduce stresses and minimize roller-edge effect.Depending on machine requirements and operating conditions, they can be customized to enhance application performance in a reliable and effi cient way.
In RKB spherical roller thrust bearings the load is transmitted from one raceway to the other under an angle of about 50° related to the bearing axis.
They can take over heavy axial loads and simultaneously they can accommodate radial loads with values of up to 55% of the axial load magnitude.
An important feature of spherical roller thrust bearings is their self-aligning capability, thanks to the design of the housing and shaft washer raceways with a large number of asymmetrical rollers and the proper conformity with the paths.
RKB spherical thrust bearings have a machined brass cage guided by a sleeve clamped in the shaft washer bore (suffix EM). The shaft washer and the cage with rollers form a non-separable unit.
The overall dimensions of the spherical roller thrust bearings are in accordance with ISO 104:1979, so that they are interchangeable with different designs, even the earlier ones (suffix B).
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Double direction thrust bearings (DDTBs) are generally composed of two rolling element-cage assemblies, one shaft washer and two housing washers. Being supported by the housing washers, they are able to accommodate very high axial loads acting in both directions, fully axially locating the shaft. The DDTBs designed by RKB come in a variety of confi gurations, in standard or enhanced execution. Their extremely high load carrying capacities, obtained through the improved internal geometry and the application of special heat treatments, make them an irreplaceable and effi cient solution in many critical applications.
RKB taper roller thrust bearings have the following separable parts: shaft washer, housing washer and rolling element assembly.
RKB manufacturing program includes the single direction type, the double direction type and the screw-down special type.
RKB single direction taper roller thrust bearings are manufactured in two constructive versions, with tapered raceway on both washers or on only one.
The rollers are radially guided by the rib of one washer. They have controlled contour to redistribute end stress concentration and provide more uniform distribution of the applied loads (suffix ZB).
这些轴承也可以生产版本without the cage to obtain the maximum axial load carrying capacity (suffix V).
岩石层双锥形滚柱推力轴承方向are normally used in the rolling mill applications associated with a multi row cylindrical roller bearing.
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