Mechanical axis, bearings and tolerance to cooperate

Bearing ( A) The function of bearing and variety: the function of bearing is supporting shaft and the shaft rotational parts make it adhere to certain rotating accuracy, accept load, but also to reduce the relative provoked friction and wear between rotating parts. Work according to the bearing can be divided into the properties of sliding bearing and rolling bearing. Rolling bearing is widely used in all kinds of mechanical bearing parts; Sliding bearing large local used in high-speed, overloading, and has bigger impact load or particularly high request to the axis of rotation precision machinery equipment, especially the demand with split structure. （ 1) Rolling bearings: (1) single-row radial ball bearing Radial bearing, deep groove ball bearing) Point: mainly accept radial load, large shaft rigidity request application places: on the gearbox and the spindle type said: cases of type 6305 (2) double row centripetal ball bearings ( Self-aligning ball bearing) Point: mainly accept radial load, double row ball, outer ring raceway is spherical shape, with automatic self-aligning properties, can automatically compensate coaxiality error due to flexure and shell deformation application places: bearing seat hole can guarantee strict alignment of parts. Model said: the cases of 1207 type, 3303 type ( Imports) (3) spherical roller bearing, The centripetal short cylindrical roller bearing) Point: the main received radial load, and also can accept a direction of axial load, have higher radial load can accept. Application places: overloading or work under vibration load. Model said cases of type 2000 (4) cylindrical roller bearing point: bearing inner and outer circle can be separated, belong to this type of bearings do not, inner ring can be at ease the axial moving application places: the bearing radial load model is used to accept said N000 Nj202E ( Import model, inner ring guard) NU206EC（ Inner ring no guard) (5) angular contact ball bearing, Angular contact ball bearing) Point: to radial load and axial load at the same time, also can accept pure axial load, limit rotational speed is higher, the bearing can accept axial load by contact Angle resolution, the greater the alpha, accept the greater the axial load can also ( α= 15°α= 25°α= 40°) Application places: angular contact ball bearings for can only accept the axial force, so this kind of bearing should be used in pairs, such as the spindle unit: ( i) Method one: the ends of the bearing outer ring is relatively narrow edge, are referred to as the device ( Commonly known as face to face) , blend the bearing's outer ring assembly, the small clearance, grinding narrow bearing outer ring. ( ii) Method 2: on both ends of the bearing outer ring side is relatively wide, called the device ( Commonly known as back to back) , bearing rigidity can progress, improve the stress of the shaft. Assembly blend bearing inner ring, the small gap, grinding narrow bearing inner ring. （ iii） Method 3: synthetic two sets of assembly, assembly precision of 0. 006-0. 014 mm gap adjustment, preload adjustment to 0. 006 mm, fit clearance is 0. 001-0. 004 mm 6 points: single row tapered roller bearing is mainly used to accept the combination of radial and axial load, Radial) , also can accept big cone Angle to the axial load of diameter, the axial load, bearing type of bearings for separation, and to use in the process of the device can adjust the bearing radial clearance and axial clearance, preloaded device can also be made. Application places: speed is not too high, rigid axial and radial load large axis, such as helical gear shaft type said: 30202 ( Imports) Divides into 7 needle roller bearing inner ring needle roller bearing ( The type 74000) And without inner ring needle roller bearing ( The type 84000) 。 Model said: example INA. ZARN2572- TU- ANA GERMANY02 / B07 - with shaft hole phi 25, cylindrical phi 72. Today a one-way thrust ball bearing ( The type 8000) Bidirectional thrust ball bearing, The type 38000) Commonly known as plane bearing. （ 2) Sliding bearing: usually give priority to with copper collar, Hydrostatic bearing, commonly known as floating bearing)