The yoke type track rollers with outer ring of thick wall can roll directly on the tray under heavy load
Summary
The yoke type track rollers with outer ring of thick wall can roll directly on the tray under heavy load. It includes pressure roller, eccentric roller, and rocking bar roller. The diameter of roller is of ball shape or cylinder ball shape. With the ball shape, the inclining position resulted during the fitting can be compensated.
Structure
Model |
| Name |
RSTO |
| No retaining edge in outer ring, yoke type track rollers without inner ring |
STO |
| No retaining edge in outer ring, yoke type track rollers with inner ring |
RNA222RS |
| Double side sealed, yoke type track rollers without inner ring. |
NA222RS |
| Double side sealed, yoke type track rollers with inner ring. |
NATR NATRPP |
| Plain retaining ring, axial guiding, yoke type track roller. |
NATV NATVPP |
| Plain retaining ring, axial guiding, yoke type track roller, full complement needle roller type |
NUTR |
| Rolling body guiding, yoke type track rollers, full roller type. |
1. RSTO and STO type yoke type track rollers
The yoke type track rollers RSTO type, without inner ring, can directly run on the quenched shaft. The STO type has inner rings, its inner ring, outer ring and the combinative needle roller retainer can be fitted separately. Because RSTO and STO type yoke type track rollers have no retaining edges and the end retaining rings, axial guiding is needed in fitting, and the guiding surface must be precisely machined at least.
2. RNA222RS and NA222RS type yoke type track rollers.
The diameter of such rollers is the same as STO series rollers but a little wider. Its double side sealed structure ensures no maintenance requested. The operational temperature range is -20-120. When fitting the yoke type track rollers without inner rings (RNA222RS) series, notice that no damage to the sealing rings should occur. The outer ring needs end side guidance.
3. NATR and NATRPP type yoke type track rollers
NATR series roller contains outer ring, inner ring, needle roller retainer and the retaining rings which are pressed and fixed by the two sides of inner ring. NATRPP series has an additional sealing ring. This kind of yoke type track rollers has huge lubricant storage space, so they can be used for long period without re-grease.
4. NATV and NATVPP type yoke type track rollers
NATV series yoke type track roller is basically the same as NATR series. The only difference is that NATV is full complement needle roller type. Therefore it can sustain heavier load under low speed, but frequent lubricating is needed. NATVPP series is structure with sealing ring.
5. NUTR type yoke type track rollers
NUTR series yoke type track roller is double row full roller bearing with retaining edge guiding outer ring. All the parts of the bearing are pressed into the sealing cage of outer ring forming a complete unit, the sealing cage, together with the thrust retaining ring form an efficient gap sealing. This yoke type track rollers can sustain very heavy load. Even with very high speed, it can bear impact axial load due to its axial guidance of its rolling bodies.
6. Tolerance
Generally, the precision of the dimensions, shape and the rotation precision of this yoke type track roller is P0 grade. The outer diameter tolerance of the yoke type track roller with an arc outer diameter is 0-/-0.05 mm, and the width of tolerance of NATR, NATV, NUTR bearings is h12.
7. Center adjustability
The yoke type track roller with diameter of cylindrical shape has very small center adjustability. With low load, the canter adjustability is 3-4 while with middle and heavy load is 5-7. The yoke type track rollers with diameter of arc shape have a center adjustability of 15-20. For bigger angle variation, the edge effect will increase with the different loads. This will decrease the life of the bearing.
8. Application and mounting
When the yoke type track rollers are fitted into a bearing cage in combination as the rolling bearings, the load selection will be in the basic rated load. When the outer ring is directly supported on the tray, the radical load will make the elasticity distortion of the outer ring. Thus the peak load will increase while the dynamic and stable load capacity will decrease. So the selection of being as yoke type track rollers column will be suitable.
Generally, the load on the inner ring of the yoke type track roller is partial load, so no tight combination of the shaft is required. The recommended shaft tolerance is shown as follows:
Yoke type track rollers
Shaft tolerance
Without inner ring
K5
With inner ring
G6
In fitting yoke type track rollers, the oil must be situated in the non-load area.