Ball and Roller Bearings Machinery's Handbook, 31st Edition
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Table 1g. Types of Rolling Element Bearings and Their Symbols NEEDLE ROLLER BEARINGS, DRAWN CUP
Symbol a
Description
Symbol a
Description
Needle roller bearing, full complement, rollers retained by lubricant, drawn cup, closed end, without inner ring
Needle roller bearing, full complement, drawn cup, without inner ring Needle roller bearing, full complement, drawn cup, closed end, without inner ring Needle roller bearing, full complement, rollers retained by lubricant, drawn cup, without inner ring
NIB NB
NIYM NYM
Needle roller
NIBM NBM
NIH NH
bearing, with cage, drawn cup, without inner ring
Needle roller bearing, with cage, drawn cup, closed end, without inner ring
NIY NY
NIHM NHM
NEEDLE ROLLER BEARINGS
NEEDLE ROLLER AND CAGE ASSEMBLIES
Symbol a
Description
Symbol a
Description
Needle roller bearing, with cage, machined ring lubrication hole and groove in OD, without inner ring
NIA NA
NIM NM
Needle roller and cage assembly
NEEDLE ROLLER BEARING INNER RINGS
Machined Ring Needle Roller Bearings Type NIA may be used with inch dimensioned inner rings, Type NIR, and Type NA may be used with metric dimensional inner rings, Type NR.
Description
Symbol a
NIR NR Needle roller bearing inner ring, lubrication hole and groove in bore a Symbols with I, as NIB, are inch-dimensioned, and those without the I, as NB, are metric dimensioned. self-alignment. This type is applicable where split housings occur or where a press fit of the bearing into the housing is not possible. Non-separable: This type consists of a non-separable unit of outer race, rollers and inner race. These bearings are used where high static or oscillating motion loads are expected as in certain aircraft components and where both outer and inner races are necessary. Special or Unconventional Types.— Rolling contact bearings have been developed for many highly specialized applications. They may be constructed of non-corrosive materi als, non-magnetic materials, plastics, ceramics, and even wood. Although the materials are chosen to adapt more conventional configurations to difficult applications or environ ments, even greater ingenuity has been applied in utilizing rolling contact for solving particular problems. Thus, linear or recirculating bearings are available to provide low friction, accurate location, and simplified lubrication features to such applications as machine ways, axial motion devices, jack screws, steering linkages, collets, and chucks. This type of bearing utilizes the “full-complement” style of loading the rolling elements between “races” or ways without a cage and with each element advancing by the action of “races” in the loaded areas and by contact with the adjacent element in the unloaded areas. The “races” may not be cylindrical or bodies of revolution but plane surfaces, with suit - able interruptions to free the rolling elements so that they can follow a return trough or slot back to the entry-point at the start of the “race” contact area. Combinations of radial and thrust bearings are available for the user with special requirements. Plastics Bearings.— A more recent development has been the use of acetal resin rollers and balls in applications where abrasive, corrosive and difficult-to-lubricate conditions exist. Although these bearings do not have the load carrying capacity nor the low friction factor of their hard steel counterparts, they do offer freedom from indentation, wear, and corrosion, while at the same time providing significant weight savings.
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