Nadella needle bearings are a standard element of a rotational motion system. They are used in applications where high load capacity, high precision and small overall dimensions are required. Nadella offers a broad range of needle bearings. Each Nadella needle bearing is produced with precision and experience gained over decades of design, production, and application. Nadella needle bearing products include:
Radial needle roller and cage assemblies have a steel cage that provides both inward and outward retention for the needle rollers. The designs provide maximum cage strength consistent with the inherent high loadratings of needle roller bearings. Accurate guidance of the needle rollers by the cage bars allows for operation at high speeds. Needle roller and cage assemblies have either one or two rows of needle rollers.
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 held in the outer ring by their ends or by grease; others have the needles mounted 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.
Drawn cup roller clutches transmit torque between shaft and housing in one direction and allow free overrun in the opposite direction. When transmitting torque, either the shaft or the housing can be the input member. Applications are generally described as indexing, backstopping or overrunning.
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. Lower hardnesses require reducing both dynamic and static load capacities.
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 also accept high speed conditions where good alignment is necessary. This can more easily be achieved using a convex inner ring raceway. Retaining needles in the outer ring enables easy installation during assembly.
Nadella cam followers are designed to run directly on various types of surface such as cams, ramps and slideways. To withstand the heavy radial loads and substantial, repeated shocks ususally imposed on this type of bearing, the various Nadella cam followers have a number of advantages. Thes include deformations that reduce the load capacity of the bearing, contact surfaces or cylindrical outer ring for reducing contact pressure, and replenishment through the shaft.
The rolling elements of a thrust bearing are retained and guided in radial pockets within the cage which is retained in relation to the plate by means of a steel ring. This assembly of parts is easy to handle and install and provides a high axial load capacity while minimizing space. The design of Nadella thrust bearings serves to reduce friction between the rolling elements and the cage that guides them. The special design of the one-piece steel cage ensures operation without wear or overheating.
Nadella combined needle bearings are designed to simultaneously support both a radial and an axial load. They include a needle thrust bearing (or roller thrust bearing) and needle cage housed in a common outer ring. These bearings form one integral unit permitting easy storage, handling and fitting. Their high radial and axial load capacities and small space requirement are a cost effective solution for a variety of applications.
Nadella precision combined bearings consist of a radial needle bearing with or without a cage, in an outer race, with a high radial thickness, each face of which acts as a raceway for a needle or roller thrust bearing. The inner ring, secured laterally between the thrust plates, acts as the inner radial raceway. Precision combined bearings take up very little space and are recommended for shafts requiring precise axial positioning, operating under high loads.
Nadella sealing rings are made from synthetic rubber and incorporate a metal insert. They have the same inner and outer dimensions as Nadella needle bushes and the radial portion of our combined bearings. The recommended housing and shaft tolerances for these bearings ensure a tight fit of the sealing ring in the housing bore and the optimum friction between lip and shaft. The simple installation of this seal, requiring no special machining, provides a very economical seal within a minimum space.
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 dimensions of the needle, diameter and length, are 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. 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.
When it is impractical to meet the shaft raceway design requirements (hardness, surface finish, case depth, etc.) standard inner rings may be used. Inner rings are made of rolling bearing steel and after hardening, their bores, raceways and end surfaces are ground. Inner rings may be used to provide inner raceway surfaces for radial needle roller bearings, needle roller bearings and needle bushes with opened and closed end.