PRECISION BEARINGS FOR MACHINE TOOLS CUSCINETTI DI PRECISIONE PER MACCHINE UTENSILI

Specifiche tecniche Combined needle and roller bearings Indicazione per esecuzione parti adiacenti SRB Radial needle roller combined bearings with axial cylindrical roller Cuscinetti radiali a rullini combinati con assiali a rulli cilindrici Cuscinetti customizzati a rulli cilindrici incrociati TOLERANCES TABLES TABELLE TOLLERANZE n

MONDIAL UNITEC Mondial is a leading company in the import and distribution of power transmission components. Mondial always provides its customers with highly qualified products matched with an excellent logistic and technical support. Mondial is an ISO 9001 certified Company. Mondial, Azienda leader nell’importazione e commercializzazione di componenti meccanici innovativi e di elevata qualità, offre un servizio costantemente adeguato alle esigenze del mercato. Un servizio che integra dinamicamente l’organizzazione commerciale con quella tecnica e logistica, proponendo una completa gamma di...

UNITEC, leading company in the design and manufacturing of spec jl precision cylindrical roller bearin 3s for machine tools and general industry, delivers high quality service and support to customers worldwide. Engineering partnership, technical and logistic services and our commercial network, supplied by different distribution channels, allows us to fulfil unique application requirements on the marketplace. UNITEC is a certified ISO 301 and ISO 14001 company, be. >ng ,ig to Mondial S.p.A. Group. Advanced technology to meet your customers requirements. Our engineers will assist you in selecting the...

2. STIFFNESS High stiffness, considerable load rating, high rotational accuracy are the essential features of the combined UNITEC RTB bearings. The axial cages with a high number of rolling elements with linear contact as well as a very high precision of the machining permit a precise and rigid movement. The size of the axial and radial rollers as well as of the inner and outer rings are carefully measured in order to obtain. The requested preloads by tightening the cap screws. The tolerances of the preload value are particularly restricted, so that a constant and uniform quality of supplies...

2. RIGIDEZZA Elevata rigidezza, grande capacità di carico, elevata precisione di rotazione, sono i requisiti fondamentali dei cuscinetti assiali – radiali UNITEC serie RTB. L’impiego di gabbie assiali ad elevato numero di corpi volventi con contatto lineare, oltre all’elevatissima precisione delle lavorazioni meccaniche, contribuisce ad ottenere un movimento preciso e rigido. Le dimensioni dei rulli, sia assiali che radiali, e degli anelli interno ed esterno sono calibrate in modo tale che al serraggio delle viti di fissaggio si ottengano i precarichi previsti.Le tolleranze, del valore del precarico...

RTB TECHNICAL SPECIFICATIONS SPECIFICHE TECNICHE Bearing assembled in housing and model for FEM analysis Schema di montaggio del cuscinetto e modello analisi FEM MOUNTING WITH THRUST WASHER (VSP) - MONTAGGIO CON RALLA DI SUPPORTO (VSP) In case a thrust washer is used in the assembly of the RTB bearing, the correct axial setting have to be evaluated. In this case, for any needed support, please contact our technical department. Nel caso di utilizzo della ralla di supporto, il cuscinetto RTB viene configurato a richiesta, valutando il corretto valore di registrazione assiale. Per ogni necessaria...

Stiffness values of rolling lements in preloaded con tions Rigidezze relative ai soli elementi volventi in condizioni di precarico teorico Stiffness values of a complete assembled bearing (°) Rigidezze relative al cuscinetto completo in condizioni di installazione di 'ferimento (°) (°) A.m. stiffness values consider the deformation of all components of the bearing and of the parts assembled with cap screws. Deviations from the actual values are possible according to the approximation of the model with respect to the real system. (1) The axial stiffness is calculated with the load applied top...

RTB TECHNICAL SPECIFICATIONS SPECIFICHE TECNICHE 3. ASSEMBLY INSTRUCTIONS As for assembly, we recommend to follow specifications indicated in figure 3.1. Usually, tolerances can lead to different mounting situations such as deflection or misalignments according to bore/outer diameter of bearings. WITH ROTATING INNER RING Rotating shaft We recommend a press fit of max 0,005 mm to impro ve accuracy and to limit friction torque. Housing We recommend to keep a small mounting clearance, except for applications demanding high precision in bearing adjustments. WITH ROTATING OUTER RING 3. INDICAZIONI...

Fig. 3.1 RTB assembly instructions Indicazioni di montaggio per RTB

RTB TECHNICAL SPECIFICATIONS SPECIFICHE TECNICHE The preload of the bearings increases the stiffness and the rotational accuracy. In presence of a load from the outside, the preload of the bearing eliminates or avoids the clearance corresponding to the elastic yielding due to the load itself. In this case, for a given range of loads, the elastic deformations caused by the load are smaller rather than in a non-preloaded bearing. Assuming approximately the stiffness is linear (rollers in contact with tracks) at the same axial load, the axial deflection is smaller in a preloaded bearings system...

δ with preload δ con precarico δ without preload δ senza precarico Fig. 4.1 (1) System without preload - sistema senza precarico (2) Preload diagram - sistema con precarico Fo Fx = System with preload Fo - forza assiale esterna δ = Axial deflection - spostamento assiale

TECHNICAL SPECIFICATIONS SPECIFICHE TECNICHE5. FRICTION ■ As for the bearings, the friction depends on many factors, the most important of which are: ■ preload ■ viscosity and amount of the lubricant ■ applied load ■ bearing size ■ rotational speed i.e.: ■ A bigger preload turns out in a bigger rolling friction torque ■ Tightening values affect considerably riotion values. As for RTB bearings the fixing of the inner ring screws reduces to zero the dimensional c r inner axial clearance as well as the elastic comp1' ssion of the inner ring. In general we recommend to use bolt class 10.9 and recommend...