FAFNIR SUPERPRECISION BEARINGS
Angular-Contact Bearings 2MM -WI type, with 15 initial contact angle is designed to meet the needs of machine builders for precision bearings which will operate at as low a temperature as possible for a wide range of speeds and operating loads. In order for machines to produce more accurate work at a higher produc- tion rate, the bearings must provide a high degree of rigidity in both axial and radial directions while operating at minimum temperatures. For example, precision machining or cutting tools impose heavier loads on bearings than those encoun- tered in precision grinding. In the former, speeds are slower and loads heavier than the latter, where speeds are high and loads light. The 2MM-WI type gives the machine builder the flexibility required to meet such variations in applications. 3MM -WI type, manufactured with 25 contact angle, is for use on applications where the loading on the bearings is predominately thrust — and a high degree of axial rigidity is a definite requirement. Typical applications for these are large vertical rotary surface grinders, horizontal and vertical disc grinders, and thrust bearing applications for heavy duty lathes where the bearings must directly carry extremely high tail stock or chucking pressure.
2MM -WO type, with 15 initial contact angle is designed for extremely high-speed applications where centrifugal force of the balls is the principal load on the bearing. Unlike the MM-WI type which has a low shoulder outer ring, the 2MM-WO type has full shoulders on both sides of the outer race and a low shoulder on one side of the inner ring. This design permits assembly with a maximum complement of balls and a one- piece cage which pilots against the precision-ground lands of the outer ring. Generally this bearing series is supplied with a separable inner ring and ball retaining cage along with special race geometry for extremely high speed operation.
2MMV and 3MMV99100WN types are available with 15 or 25 contact angle variations and have been developed to operate under the demanding requirements of high speed machine tools. They incorporate design features which permit operation at higher speed than standard angular contact ball bearings. The bore, outside diameter, and width are the same as the MM9100 series.
This series is designed to operate at rotational speeds 20% greater than the MM9100 series, with no increase in operating temperature. The greatest advantage of these series is at speeds greater than 500,000 DN (Bore in mm x RPM). Silicon nitride balls (ceramic) and precision machined ball separators are available and, when used, the ultimate performance will be achieved.
2MMV and 3MMV99100WN Types