Nadella Combined Needle Roller Bearings as a Cost-Effective Alternative for Industrial Machinery Assemblies
The Nadella Group brings years of experience in product development, design, manufacture and application to every bearing it produces.
Since 1930, Nadella has been known on the world market as a leading manufacturer of needle roller bearings. Needle Roller Bearings are one of the most important components of machines and mechanisms and are used wherever high load carrying capacity, high running accuracy and small dimensions are required. Today, Nadella offers one of the widest ranges of needle bearings in the industry. The strength of the company's manufacturing programme is its ability to produce high quality standard and special products at competitive prices.
Nadella's RAX combination needle roller bearings are designed to support both radial and axial loads simultaneously. They consist of a needle roller thrust bearing or a cylindrical roller thrust bearing and cage with needle rollers housed in a common outer ring.
Technical data for axial needle roller bearings and needle roller and cage assemblies are given in the relevant sections of the Nadella catalogue. These products form a single, complete design that allows easy transport, storage, use and installation. The high radial and axial load carrying capacity of the bearings, together with the need for a small footprint, enables cost effective solutions.
The design calculations for combined needle roller bearings consider the axial and radial components separately without converting the axial load into an equivalent radial load.
The independent operation of the thrust bearing and the needle cage eliminates any negative mutual influence on axial and radial rotational accuracy. For example, axial thermal expansion of the shaft has no effect on the running accuracy of the radial component of the bearing.
Bearings can be used without inner or thrust rings if the shaft surface is sufficiently hard and machined to allow it to be used as a raceway. A shaft surface hardness of 58-64 HRC Rockwell is sufficient for effective use of these bearings with the indicated load carrying capacity without inner or thrust rings. Lower hardness values will result in a lower static and dynamic load carrying capacity of the bearing, both axially and radially.
RAX 700 and RAXF 700 Series Combined Needle Roller Bearings
RAX 700 Series Combined Needle Roller Bearings have a single piece outer ring made from precision formed, heat treated and hardened thin sheet steel. The shape of this outer ring completely eliminates any weakness in the junction area between the axial component and the radial component, even after the latter has been tightly fitted into the housing.
The design of this type of low cost combined bearing is very robust and space saving, resulting in very cost effective solutions. They are often used as an alternative to a machine assembly consisting of two separate needle roller bearings due to their ease of use and quick and simple mounting.
RAXF 700 series needle roller and cage combination bearings with a closed outer ring on one side provide effective sealing of shaft ends and do not require bearing housings with plugs or end caps.
The Nadella Group manufactures standard RAX 700 series combined needle roller bearings for shaft diameters from 5 to 45 mm (RAXF series for shaft diameters from 12 to 30 mm) with radial components designed for static loads from 1. 95 to 55 kN (RAXF series from 7.20 to 51 kN) and dynamic loads from 2.15 to 24.8 kN (RAXF series from 6.30 to 26.2 kN) and with axial components designed for static loads from 6.35 to 109 kN (RAXF series from 17.7 to 96 kN) and dynamic loads from 3.15 to 21.8 kN (RAXF series from 6.90 to 20.4 kN).
Combined needle roller and needle roller bearings are standard in the RAX 400 and RAX 500 series
RAX 400 and RAX 500 combined needle roller bearings consist of a separately machined thrust plate and outer ring of the radial component, joined by a robust metal insert. This arrangement prevents localised stress in the bearing and eliminates weak points in the joining area of the two components, thereby eliminating the risk of damage during installation or operation.
While the RAX 700 series combined needle roller bearings should be considered primarily for economic reasons, the RAX 400 or RAX 500 series solid outer ring combined needle roller bearings should be used when operating conditions require higher load carrying capacity and increased running accuracy. In addition, these bearings can be supplied in a higher "tool quality" version RAXN.
Nadella Group manufactures standard RAX 400 and RAX 500 series needle roller and cage assemblies for shaft diameters from 10 to 70 mm with radial components designed for static loads from 7.16 to 84.7 kN and dynamic loads from 5.90 to 36.1 kN and with axial components designed for static loads from 10.9 to 295 kN and dynamic loads from 5.0 to 77 kN.
RAXPZ 400 and RAXPZ 500 series combined needle roller bearings
These bearings have an integral thrust ring held by a special steel washer together with a backing plate and roller cage. They are better protected against dust and metal particles and are therefore mainly recommended for use in machine tool spindles.
The RAXN 400 and RAXN 500 tool quality combined needle roller and cage bearings are manufactured with the same dimensions as the RAX 400 and RAX 500 series, but with higher accuracy in terms of ring ovality and thickness and axial runout of the thrust bearing. The RAXNPZ 400 and RAXNZ 500 series bearings, which are also available with a protected thrust ring, are particularly recommended for use in machine tool spindles.
Rated Load Capacity of Combined Needle Roller Bearings
Design calculations for combined bearings are carried out separately for the axial and radial components without converting the axial load into an equivalent radial load. The basic load ratings for each combined bearing of series RAX400, RAX500 are given in the catalogue dimension tables. RAX700 and RAXF700 series combined bearings have a limitation on the maximum allowable load, both axial and radial, due to the thinner outer ring.
Dynamic Load Capacity of Combined Needle Roller Bearings
The dynamic load carrying capacity of a bearing is the constant radial load that the bearing can carry for one million revolutions before the first signs of material fatigue appear on the rings or rolling elements. For a thrust bearing, this value per million revolutions assumes a constant axial load centred on a line aligned with the axis of rotation.
Lubrication of Combined Needle Roller Bearings
In the case of relatively high axial loads and the possibility of using oil as the desired lubrication method, RAX 500 series bearings should always be considered and selected. Combined bearings with a dust cap can also be lubricated with oil, although their design makes them most suitable for grease lubrication. Combined bearings are normally supplied in a package with a preservative anti-corrosion compound applied, which is not a lubricant. The bearings can be used in oil or grease lubricated equipment without removing this compound. However, it is often advisable to remove the preservative compound before fitting the bearings with a suitable lubricant in order to achieve optimum lubrication performance and to minimise the likelihood of grease lubricated bearings being confused with bearings containing a preservative compound.
Needle roller bearings from the Nadella Group can be used in virtually all industries where linear motion and radial rotation systems are required, but are particularly common in textile machinery. Other applications include agricultural machinery, metal cutting machines, printing presses, compressors and turbines, gearbox pinion bearings, rack and pinion mechanisms.
About Nadella Group
Founded in France in 1930 as a rolling bearing manufacturer specialising in various types of needle roller bearings (needle bushes and bearings, guide rollers, thrust and combined needle roller bearings), the Nadella Group is now also focused on the development, design and manufacture of various types of linear motion systems and modular linear actuators.
Today, the main activities of the Nadella Group are concentrated in these two sectors: linear technology and bearing technology.
The activities of the first division are entirely focused on the design and manufacture of components, modules and linear motion systems, not only in standard configurations, but also in special customised solutions to meet the needs of customers in industrial applications (machines for woodworking, metallurgy and metal rolling, manipulators, assembly lines, packaging systems, printing machines, metal cutting machines and other sectors).
The company's second division deals with power transmission system components and needle bearings.
The Nadella Group is headquartered and has production facilities in Italy, with subsidiaries in Germany, the USA and China.
The Nadella Group is one of the world's most recognised brands in power transmission components and is the preferred partner of many of the world's most prestigious original equipment manufacturers.
CMT GmbH - Platinum Partner of the Nadella Group
As a platinum partner of the Nadella Group, CMT GmbH supplies all of the company's products. When you turn to us, you benefit from the most attractive prices, the shortest delivery times for this manufacturer's products and can rely on the professional advice that is always available to you when selecting Nadella products.
