NRB Bearings

NRB manufactures needle/roller thrust bearings in different constructional features. Design features of one of the types is explained below The rolling elements of a thrust bearing are retained and guided in the radial pockets within the cage (1). The latter is itself retained in relation to the plate (2) by means of a steel ring (3). This assembly of parts is easy to handle and install and provides a high load capacity whilst occupying minimal space. The design of NRB thrust bearing serves to reduce to a minimum the friction between the rolling elements and the cage that guides them. Given correct instal-lation and adequate oil lubrication, the co-efficient of friction will be between 0.003 and 0.004 for needle thrust bearings and between 0.004 and 0.005 for roller thrust bearings. The result is due principally to the design of the one piece steel cage which has a special curvature that guides the rolling elements by their ends along their centre lines. Thus, the loads imposed on the cage by the rollers cannot create components parallel to the axis of rotation and therefore no increase in internal frcition is generated, and correct operation without wear or overheating is ensured. In addition, this special curvatures gives the steel cage great rigidity and being relatively thin provides maximum space for the lubricant. THRUST PLATES The plate incorporated in the thrust bearing is made from hardened bearing steel and forms one of the raceways for the rolling elements. The opposing raceway is generall provided by a separate thrust place of similar design supplied by NRB. When the thrust bearing is centred by the revolving part, the thrust plate must be centred by the stationary part and vice versa. If the revloving part and the stationary part are noticeable eccentric to each other, the thrust bearing with integral plate must without exception be centred by the revloving part. The second raceway for the rolling elements may also be formed by the face o

NRB manufactures two types of thrust bearings that effectively counter the very high shock loads on the Steering King Pin. These are : 1. Full Complement type ( without cage ) 2. Caged type These bearings consist of two tapered thrust races, rollers, cages ( in case of Caged type ) and an outer retainer which holds the components for the purpose of transporting and installation of bearings. Some of the standard sizes are listed below. Special sizes and types can be made available to suit specific requirements that customers would have.

Caged needle bearings possess an outer ring made from through hardened bearing steel. The cage, guides the needles and retains them in the outer ring . The bearings may be used without an inner ring if the shaft journal serving as a raceway is of sufficient hardness and has the correct surface finish. To ensure that the full load capacity of these bearings is achieved, a hardness of 58-64 HRC is required. A lower hardness will entail a reduction in the load capacities (both dynamic and static) as shown in table of dimensions (see Technical Section) TYPES OF BEARINGS Without inner ring With inner ring NB NBI RNA NA Dimensions of series 49 in accordance with ISO Standard 1206 TOLERANCES OF THE INNER AND OUTER RINGS The inner and outer rings of caged bearings are manufactured in conformance with the tolerance class of ISO 1206. For high precision applications, bearing rings can be made to closer tolerances corresponding to classes 6, 5 and 4 of ISO 492 (DIN 6290 ) denoted by symbols P6,P5,P4

Full complement needle bearings have a through-hardened outer ring which results in high static and dynamic load capacities and an ability to withstand overloading, shocks and vibration. They are particularly suitable for operations involving oscillating motion but may not accept high speed conditions where good alignment is necessary .This can more easily be achieved using a convex inner ring raceway. The retention of needles in outer ring enables the bearings to be installed easily during assembly. These bearings are available with or without an inner ring from 12 mm bore size. Standard complete bearings type NA have an inner ring with convex raceway form. If extra wide inner rings or rings with lubrication hole are required, they should be ordered separately for use with corresponding RNA series.

Hub Pin Kits consist of a precision ground shaft having one needle bush fitted at each end. Hub Pin kits are available with seals depending on the application. It is used in Scooters and three Wheelers. Hub Pin refrence Customer Vechicle SP900 14/12 Bajaj Scooter and Three Wheeler SP900 14/20 Bajaj Classic SP900 14/18 Greaves Garuda SP 900 14/16 LML Scooter SP90014/16/S* LML Scooter

For a bearing with a given internal diameter, there is a choice of inner rings with the same diameter Ci but of different widths. Normally, the width of the inner ring should never be less than that of the bearing. Alternatively cylindrical inner ring wider than the bearing may be used to permit the fitting of a sealing ring, which would locate on the extended portion at one end of the bearing. In this case, if the inner ring has an oil hole, care should be taken to ensure that the hole does not coincide with the ends of the needles. Inner rings having the suffixP, inner rings series 49 and inner rings series 19 000 and 20 600 are not to be used (without first consulting NRB Technical Department) with needle bushes not having the suffixP, nor with the combined bearings RAX (or RAXF) 700. The inner rings indicated by an asterisk may be produced with a convex outer diameter under the designation IMR6. Inner rings IMR6 are intended principally for use with DL series full complement needle bushes, to increase the allowable misalignment tolerance and must always be positioned immediately below the needle bush, the maximum axial displacement being 5% of the bearing width. Inner rings may also be supplied with oil hole (designation IMC). Please consult NRB Technical Department with regard to specific requirements

Single row deep groove ball bearings is the most popular of all rolling bearings. The design of uninterrupted raceway shoulders enables the bearings to support radial thrust (in either direction), or combined loads and bearings are suitable for high speed operations. Non-separable type of design make it easier to handle the bearing and can be mounted either fixed (Fig. 1) or floating (Fig.2). BEARING TYPES NRB deep groove ball bearings are available in 60, 62 and 63 series and are available in different types as illustrated in Fig. 3. Please check for availability. NRB also manufactures special sizes of ball bearings against specific requirements of customers. Some sizes are listed in the table of dimensions - Other sizes. NRB would be pleased to develop new special sizes provided the quantities are large. PREFIXES GB Double row angular contact ball bearing, 40 contact angle JB NRB special ball bearing QJ Four Point contact ball bearing E, L Single row ball bearing ( Magneto Type) LS Single row ball bearing ( Inch series)

Needle bushes consist of a thin, heat treated outer ring formed from accurately controlled sheet steel encasing a set of needles. Bushes may have a full complement of needles retained in the outer ring by their ends or by grease, others have the needles retained in a cage which is prevented from moving laterally in the outer ring. These bearings which occupy very little radial space are particularly economical to use and possess a high load capacity, relative to their size. They should be selected in preference to other bearings when conditions of mounting and operation permit. When needle bushes are used without an inner ring and needles rotate on a shaft of suitable hardness they occupy minimum space and therefore provide a very satisfactory solution Maximum load capacity is obtained with a shaft hardness under needles of atleast 650 HV.A lower hardness is acceptable if loads and required life permit, please consult NRB. Hardened inner rings can be supplied for most NRB needle bushes. They remove the necessity to harden the shaft and enable the bearings to accept full load capacity. Needle bushes are normally supplied with rust preventive oil except where a special grease has been requested. Needle bushes SL, CN and CNS types where needles are retained by grease are supplied with grease. TYPES OF NEEDLE BUSHES In metric dimensions Without Oil hole. Full complement needle bushes Caged needle bushes Retained needles Grease-retained needles Open (fig 5) Closed end (fig 6) Open with seal (fig 7) Open (fig1) Closed end (fig.2) Open (fig.3) Closed end (fig.4) DL DL..P DLF DLF..P SL SL..P CN , CNS DB DB..P DBF DBF..P DB..E DB..PE

NRB manufactures a wide range of Bottom Roller Bearings for supporting bottom rollers in Ring Spinning frames and speed frames of textile industry. NRB Bottom roller Bearings conform to International Standards. Holders (locating caps) for these bearings are made suitable for various sizes of roller stands. Special sizes of Bottom Roller Bearings are also manufactured as per customers requirements. FEATURES NRB Bottom Roller Bearings-UN Series are specially constructed Needle Roller Bearings for long and trouble free service. Every component of the bearing is manufactured to strict quality norms. The stringent limits of manufacture ensure the running accuracy of the bearing. The outer ring (1) of the bearing is crowned to accommodate some misalignment in the Roller Stands. Crowning also helps in preventing early failure of the bearing by distributing the load uniformly. The inner ring (2) has knurling on its flanges, which provides an effective seal to prevent entry of fibres in the bearings and protect it from damage. NRB Bottom Roller Bearings UN Series incorporates a steel cage split in two halves or plastic cage (3) The design of cage pockets ensures that the needles (4) do not fall and also give them positive and accurate guidance. Lubrication to the bearing is effected through the grease nipple (5). The bearing is secured on the roller stand very easily by holder (locating cap) (6). Holder (locating cap) in different designs as per customers requirement can be supplied.

Tapered Roller Bearings main characteristics are the ability to handle high combined axial and radial loads. It consists of two components: a outer ring or cup, and an assembly incorporating a tapered inner ring with cage and tapered rollers, knows as the cone assembly. The tapered rollers are held in the cone by a pressed steel cage, which comes in contact with the cone flange SAILENT FEATURES Excellence in quality of the Tapered Roller Bearings is achieved by focussing on critical aspects like: The internal design of the bearing The quality of the material used and its heat treatment techniques Precision of the machining process Stringent inspection procedures

In certain applications, the limited amount of space available for bearings and the loads to be supported require the use of a full complement of needles independent of any system of retention. The length of the needle is determined in relation to the load capacity required. The needles are placed directly between shaft and housing without the use of inner or outer rings. Thus a shaft of maximum diameter is permissible to increase rigidity and load capacity. In rotating applications where the load capacity requires the use of needles that are long in relation to the shaft diameter, it is preferable to employ two rows of needles of equal length separated by a spacer ring. In such cases, the needles must be selected with diameters in the same tolerance class. This arrangement is particularly recommended for mounting parts such as long idler wheels, especially where they are subjected to rotational torque. RACEWAYS Maximum load capacity is obtained with hardened inner and outer raceways of surface hardness 58-64 HRC. Parts used for lateral retention of needles at their ends should be of equivalent hardness. The inner and outer raceways should both be aligned on installation and before operation under load. In the case of parts fitted with a single row of needles , the inner raceway may be ground convex to allow misalignment. A convexity permitting misalignment of 1 in 1000 (or up to 2 in 1000 in cases of instantaneous overloading) does not reduce the calculated load capacity. This convexity, which also depends on length of the needle, may be produced on a separate inner ring or directly on shaft journal using a grinding wheel with concave profile obtained by inclining the diamond impregnated cutting wheel. Further technical information is available on request.

The NRB self-aligning spherical roller bearing is a combination radial and axial bearing,designed to operate even if the shaft and housing are, or become, misaligned under load. This type of heavy duty bearing is the favoured choice when conditions include heavy loads, plus difficulties in establishing or maintaining housing alignment, or when shaft deflection can be expected. Shaft deflections and housing distortions caused by shock or heavy loads,which lead to misalignment,are compensated for by the internal self-alignment of the bearing elements during operation.Corner loading of rollers, a condition that limits service life on other types of bearings,cannot develop in spherical roller bearings.Optimum bearing capacity can often be realized with up to 1 degrees of misalignment , depending on the size and series of bearing selected. The inherent compensation for misalignment provided by spherical roller bearings offers the designer the opportunity to use weldments for housing frames instead of complex castings, eliminating high cost machining operations. Even when castings may be preferred ,bore alignment is less critical if spherical roller bearings are specified. Unit design and construction also make the spherical roller bearing convenient to handle during installation or maintenance. Most types have circular groove and lubricating holes in the outer rings. This feature facilitates more effective lubrication. NRB manufactures spherical bearings with cylindrical or tapered bore. Tapered bore series may be used either in Plummer blocks or conventional housings. DESIGN FEATURES The proven design of NRB E type of bearing has shown that a design without a central guide rib is both reliable and efficient. In this design of bearing the roller guidance is provided by the tracks and cages. Now, also the other type of bearing., type EA from NRB is comprised of minimum number of components. A number of years of experience and precise control of the ma

NRB crank pins are high precision components which are needed in the connecting rod bearing arrangement at big end position of 2-stroke and 4-stroke engines. Cranks pins undergo the severe operating conditions of particular load, high temperatures and adverse lubrication. The application demands the use of very high quality crank pins. Design, raw material, heat treatment parameters, surfacve finish values and form tolerances of NRB crank pins confirm to OE specifications

NRB Cylindrical Roller Bearings are most suitable for high radial loads and capable of operating at high speeds. Thermal expansion of shaft in axial direction is best taken care of by using a cylindrical roller bearing with plain inner ring (type NU) or plain outer ring (type N). Cage and roller assembly with two ribbed rings ( either the inner or outer ) is separable from the other ring, and thus can be mounted independently. This feature simplifies the mounting of a cylindrical roller bearing when interference fit is to be considered for both the inner and outer rings NRB also manufactures special types of cylindrical roller bearings as per the specific requirements of the customers. Refer to table of dimensions - Special sizes. Please consult NRB before selecting a bearing from the list of special sizes for new applications. NRB would be pleased to develop new sizes as per the specific requirements provided the quantities are large.

Needle cages are inexpensive and very easy to install. They can be fitted by hand without the use of tools. They may be manufactured in two parts and can then be mounted on an inner raceway between two shoulders. This arrangement allows the rigidity of the shaft to be increased. The double cage, that is one having two rows of needles, comprises two bearings side by side in one continuous unit. It allows parts such as idler pinions to be fitted easily and ensures their stability. The double cage can also be manufactured in two separate parts. NRB manufacture cages in steel, polyamide, brass and aluminum bronze materials. Needle rollers used in these assembLes are made of high carbon chrome steel , hardened, ground and lapped to close tolerances for diameter and roundness. NRB cages, manufactured in steel, present the following advantages: Great rigidity preventing deformation during handling Good mechanical stability that resists ageing and ensures long operational life without excessive wear whilst maintaining the geometrical shape of the cage at high temperatures Excellent resistance to synthetic additives contained in many lubricants Minimal thickness allowing maximum oil penetration thus assisting effective lubrication Low weight minimising the centrifugal effects of rapid acceleration

One more step towards excellence In its constant endeavor to provide Indian industry with world-class products, NRB now introduces high quality steel balls. Designed to meet the requirements of a wide range of applications, NRB steel balls are manufactured in an entirely imported facility purchased from Torringtons FAFNIR division in U.K. Superior quality raw materials, imported from the worlds finest steel mills, combined with modern manufacturing technology, bring you the best available SAE 52100 steel balls. Symbols and Definitions Dw: Nomial Ball Diameter The diameter value which is used for the purpose of general identification of a ball size. Dws: Single Diameter of a Ball The distance between two paralled planes tangent to the surface of the ball. Dwm: Mean Diameter of a Ball. The arithmetic mean of the largest and smallest actual single diameters of the ball. VDws: Ball Diameter Variation