INA Yoke type track rollers are single or double row units mounted on shafts or studs. They comprise thick-walled outer rings with a profiled outside surface and needle roller and cage assemblies or full complement needle roller or cylindrical roller sets.
Yoke type track rollers can support high radial loads as well as axial loads arising from slight misalignment and skewed running; they are suitable for applications such as cam gears, bed ways and conveying equipment.
The INA bearings are available with and without an inner ring and in both sealed and open versions.
Series PWTR is supplied as an X-life design. Due to a modified material and the optimised raceway geometry of the outer rings, the basic rating life has been increased by up to 30%.
The static and dynamic load carrying capacity has also been increased. At the same time, the stress placed on the mating track has been reduced as a result of the optimised lateral surface profile and its improved surface quality.
Due to these measures, highly robust bearing arrangements with an extended operating life can be achieved.
Outside surface profile of the outer ring
INA Yoke type track rollers with a crowned outside surface are predominantly used in practice since they are often inclined in relation to the mating track and edge stresses must be avoided.
The radius of curvature of the outside surface is R = 500 mm.
The series NATR..-PP, NATV..-PP, NUTR and PWTR..-2RS have an outside surface with the optimised INA profile.
In yoke type track rollers with this curvature profile:
- the Hertzian pressure is lower
- edge loading under tilting is lower
- wear of the mating track is reduced
- the operating life of the mating track is extended.
INA Yoke type track rollers without inner ring
Yoke type track rollers RSTO and RNA22..-2RSR do not have an inner ring. They are particularly compact but require a hardened and ground raceway on the shaft or stud.
INA Series RSTO is not self-retaining. This means that the outer ring and the needle roller and cage assembly can be fitted independently of each other.
In RSTO and RNA22..-2RSR, the rolling elements are guided by a cage. These designs do not have axial guidance of the outer ring. Axial guidance of the outer ring and needle roller and cage assembly must be provided in the adjacent component
INA Yoke type track rollers with inner ring
These INA yoke type track rollers are used if the shaft or stud does not have a hardened and ground raceway.
STO is not self-retaining. This means that the outer ring, needle roller and cage assembly and inner ring can be fitted independently of each other.
With cage, with full complement needle roller or cylindrical roller set
The INA bearings series STO, NA22..-2RSR, NATR and NATR..-PP have a cage. The series NATV and NATV..-PP have a full complement needle roller set, while yoke type track rollers NUTR, PWTR..-2RS and NNTR..-2ZL have a full complement cylindrical roller set.
Bearings without a cage have the largest possible number of rolling elements and therefore have particularly high load carrying capacity. Due to the kinematic conditions, however, the speeds achievable with these bearings are somewhat lower than those achievable with the cage-guided yoke type track rollers.
STO and NA22..-2RSR do not have axial guidance of the outer ring. This must be provided in the adjacent construction.
In NATR and NATV, axial guidance is provided by contact washers and axial plain washers. In NUTR, the outer ring is guided by the rolling elements, in PWTR..-2RS and NNTR..-2ZL it is guided by the central rib and the rolling elements.