FAG Powerful Bearings for Driven Tools Application specific solution
Application specific solution FAG Powerful Bearings for Driven Tools Ordering example: B7198-F-P4-UL The bearings make a convincing case The bearings are matched for universal on the basis of: use and can be fitted in any arrangement 16174 Figure 1 FAG bearings for power tools High precision turning and milling operations are now carried out in many cases using power tools and typically with short cycle times and in restricted spaces. With the new FAG high precision bearing series for driven tools, specific bearings are now available high axial and radial load carrying capacity high rigidity high running accuracy minimal maintenance requirements (especially in the case of the sealed bearing design) long life. Bearing designs bearings with steel balls have a contact angle of 3. This improves the axial load carrying capacity and rigidity and nevertheless ensures adequate reserves for combined radial and axial loading. The accuracy class corresponds to P4. according to the requirements of the machining task. As standard, bearings are supplied without seals and without grease. For problem-free fitting and replacement, units sealed on both sides and greased for life are also available. In the case of the sealed design, benefits in terms of time and security are provided not only by its capacity for immediate fitting but also by the selection already made on the type, quantity and feed method of the lubricant. In light of the frequent swivel movements during tool changes, it is very important to keep the lubricant in the rolling contact area. This is where sealed bearings make an additional contribution, Figure 2. that have been precisely optimised in terms of their contact angle, internal design and running accuracy for this application, Figure 1. The advantages for the user are more precise machining results, very high machining performance and high productivity. 16179 Figure 2 FAG bearings for driven tools, sealed on both sides
Driven tools as an area of use: a special solution for a specific application The bearing arrangement in a driven tool must be capable of supporting high machining forces while requiring little space. During drilling into solid materials using solid carbide drills in particular, very high axial forces occur. Milling operations are also sometimes encountered that involve high combined radial and axial loading. For precision machining, not only high load carrying capacity but also high rigidity and very high running accuracy are essential, Figure 3 and Figure 7, page 5. The speeds occurring are lower, due to the small bearing dimensions, than in the case of main spindles in milling machines. The speed parameters are generally in the range from 5 to 1 min 1 mm. The bearings are generally lubricated with grease in order to allow simple changing of the tool holder. Under the particular operating conditions in driven tools, the new FAG bearings are superior in terms of rigidity and load carrying capacity to standard bearings with a 25 contact angle. The steel bearings with a contact angle of 3 represent a bearing arrangement solution optimised to match the particular requirements of this machining. Figure 3 Tool holder with driven tools Increased performance compared to spindle bearings Tool holder for drilling and milling, supported by three rigidly adjusted bearings of size 7198 and an additional needle roller bearing, Figure 4. Assessment criteria: contact pressure, bearing kinematics and displacement at the shaft collar. 1614E The selected arrangement of bearings depends on the tool used and the machining forces occurring. The bearings should therefore be suitable for universal mounting in different arrangements. z y x 16116 Figure 4 Application example: tool holder for milling and drilling
Through the use of the bearings for drilling, the permissible axial force is increased by 24% compared to the standard design. Due to the higher axial rigidity, the axial deflection is 1 kn 8 25 m 2 F A = 5 kn even reduced by 3%, Figure 5. Despite the larger contact angle, the radial load carrying capacity of the bearings is comparable with the load capacity of standard designs due to the optimised internal design. Permissible axial load 6 4 2 Axial deflection 15 1 5 On the assumption that the axial force is half as great as the radial force occurring, the example with bearings presented 16115 shows that the radial force occurring can even be 8% higher, with a radial Figure 5 Performance comparison: permissible axial load and axial deflection deflection reduced by 16%, Figure 6. 1 F A =,5 F R 25 F A =,5 kn F R = 1kN kn m,8 2 Permissible radial load,6,4,2 Radial deflection 15 1 5 16151 Figure 6 Performance comparison: permissible radial load and radial deflection
Summary The new FAG bearings were developed specifically for driven tools, Figure 3, page 3 and Figure 7. Due to the 3 contact angle, they are particularly suitable for supporting high axial forces. They are directly interchangeable with spindle bearings of series B719 and B7 and offer even more precise machining results and higher cutting performance for the application. Figure 7 Driven tool (section) 16153
MATNR 3684856- / SSD 18 / GB-D / 2911 / pdf only Your contact Dr. Martin Voll Telephone +49 9721 91-136 e-mail martin.voll@schaeffler.com Schaeffler KG Georg-Schäfer-Straße 3 97421 Schweinfurt (Germany)