组合式向心--推力滚轮

COMBINED RADIAL-THRUST BEARINGS

           Needle and retainer assembly, needle bearing and drawn cup needle roller  bearings are all moving tip bearings . 
  They can be used as positioning bearings with combined with stop thrust rings or under small load at low speed and being 
  fully lubricated. Other positioning bearing always have the problem of much space occupied.
          Combined RTL-needle bearings are single directional positioning bearings or the positioning bearings with minimum 
  radically sectional height .  If the Centripetal needle bearings are used with thrust ball bearings or cylindrical roller
  bearings in combination , the applicable range will be greatly expanded. The combined RTL-needle bearings are mainly used 
  in transmission engineering and tooling machines such as the bearings in the main shaft of a drill press , drill sleeve , 
  positioning central shaft, worm , spanner teeth head and so on and so forth..

Structure

NKIA	Centripetal needle bearings and single direction angular contact ball bearings combination, used for axial light load
NKIB	Centripetal needle bearings and double direction angular contact ball bearings combination, used for axial light load
NX NX...Z	Centripetal needle bearings and densely fitted thrust bearings combination, with fixed cage, used for middle axial load
NKX NKX...Z	Centripetal needle bearings and thrust ball bearing combination, with or without fixed cages ,used for axial heavy load, DIN4529
NKXR NKXR...Z	Centripetal needle bearings and thrust ball bearing combination, with or without fixed cages ,used for axial very heavy load, DIN4529

Needle-angular contact ball bearings NKIA

This kind of bearings will greatly save the space of the rolling bearing, used for radical heavy load or axile light load. The needles bear the radical load. Axile load will not be greater than 25% of the radical load. If the axial force effects in two directions, two needle-angular contact ball bearings which will effect each other can be fitted when the spaces between the bearings are not big.

Needle-angular contact ball bearings NKIB

This is a kind of RTL-needle-angular contact ball bearings bearing double directional forces , the heavy radical load and the double axle light loads, this will make the shaft positioned in axial direction. The axile direction gap is 0.08?.25mm. axial load can not be greater 25% of radical load. The two separate inner rings are convenient for fitting, but they can not be exchanged. The two halves will be clamped tightly in axial direction.

Needle-thrust ball bearings NX and NX...Z

This kind of bearings can bear radical load or the middle single directional axial load through densely fitted needles. This is a kind of space saving bearings which will make allow very small spaces between the shafts (for instance: the multi-shaft boring head or multi-shaft drilling units). The minimum central dimension is the outer ring dimension of the bearing. The bearings can bear the axial load through out stop ring of the outer ring, the bearing seat hole shoulder or the inner stop ring support in the bearing seat hole.
NX series bearings should be lubricated with oil lubricants, so the tray on the shaft must be quenched and ground. If the shaft is not quenched, inner ring should be supplied. (see the dimension table)
If two NEEDLE-HRUST BALL BEARINGS are fitted oppositely , alternative axial loads can be sustained. It is suggested to pre-tighten the bearings without load with springs. In this way, the heat expansion can be compensated and the operational noise can be lowered. When the speed is greater than 0.2n1oil , the pre-tightening value should be 1% to 2% of the axial rated dynamic load.

Needle-thrust ball bearings NKX and NKX...Z

Beside the radical load, this kind of bearings can sustain single axial load. When bearings with fixed cages are to be ordered, please suffixed "Z" behind.
As to the relative sealing, the inner ring and double directional axial load, the details are the same as NX AND NX...Z.

Needle-thrust cylindrical roller bearings NKXR and NKXR...Z

These are bearings series which have bigger axial load capacity. The bearings with fixed cages can also supplied (suffixed with"Z"))
As to the relative sealing, the inner ring and double directional axial load, the details are the same as NX AND NX...Z

Standard grade bearings

              For all bearings supplied, the dimensional tolerances and geometric precision are in compliance with
    DIN 620 and the tolerance grade of P0 with normal radical gap C0. The only exception is NK1B series which have
    narrower inner aperture with bigger tolerance so that they can be used with the shaft with K5 tolerance in tr-
    ansit combination.
              Table 1 shows the tolerances applicable to the fitting for general purposes:
           Table 1 Fitting tolerance

Series No	Shaft tolerances		Hole tolerances
	Without inner ring	Inner ring
Needle -ngular contact ball bearings NKIA	-	k52)	M62)
Needle-ngular contact ball bearings NKIB
Needle-hrust ball bearings NX	k5	k5	K6 M6(Rigid supplrt)
Needle -hrust ball bearings NKX1)
Needle -hrust cylinder roller bearings NKXR1)

1)In bearing hole, the diameter of he thrust bearings must be 0.5mm bigger than nominal diameter D1 or D2 to avoid interference combination.
2)To ensure normal functions, no closer combination than K5 shaft and M6R hole should be used.

特殊要求

If the bearings combination of high precision, the listed bearings in compliance DIN 620 P6 AND P5 grades tolerances can be supplied.
For NKIA and NKIB series bearings, only the bearings with initial radical gap between C2 to C3 can be supplied.