THK Cross Roller Ring is a roller bearing with high rotation accuracy capable of bearing loads in every direction. Because it has orthogonally arranged cylindrical rollers, it can bear loads in every direction.
With THK Cross-Roller Ring, cylindrical rollers are arranged with each roller perpendicular to the adjacent roller, in a 90° V groove, separated from each other by a spacer retainer. This design allows just one bearing to receive loads in all directions including radial, axial and moment loads.
Since THK Cross-Roller Ring achieves high rigidity despite the minimum possible dimensions of the inner and outer rings, it is optimal for applications such as joints and swiveling units of industrial robots, swiveling tables of machining centers, rotary units of manipulators, precision rotary tables, medical equipment, measuring instruments and IC manufacturing machines.
High Rotation Accuracy
The spacer retainer fitting among cross-arrayed rollers prevents rollers from skewing and the rotational torque from increasing due to friction between rollers. Unlike conventional types using steel sheet retainers, the Cross-Roller Ring does not cause unilateral contact of roller or seize. Thus, even under a preload, the Cross-Roller Ring provides stable rotation.
Since the inner and outer rings are designed to be separable, the preload can be adjusted, and this feature enables accurate rotation.
Easy Handling
The inner and outer rings, which are separable, are secured to the Cross-Roller Ring body after being installed with rollers and spacer retainers in order to prevent the rings from separating from each other. Thus, it is easy to handle the rings when installing the Cross-Roller Ring.
Skewing Prevention
Increased Rigidity (Three to Four Times Greater than the Conventional Type)
Unlike the thin angular ball bearings installed in double rows, the cross array of rollers allows a single cross-roller ring unit to receive loads in all directions, increasing the rigidity to three to four times greater than the conventional type.
Types of THK cross roller rings
Model RU (Integrated Inner/Outer Ring Type)
The integrated design of the unit’s inner and outer rings, with mounting holes on both rings, eliminates the need for a special fl ange or housing and enables easy installation. Mounting has virtually no effect on performance, which ensures stable, accurate rotation and torque. Can be used for both outer and inner ring rotation.
Model RB (Separable Outer Ring Type for Inner Ring Rotation)
THK cross-Roller Ring basic type, with a separable outer ring, and an inner ring integrated with the main body.It is used in locations where the rotational accuracy of the inner ring is required. It is used, for example, in the swivel portions of index tables of machine tools.
Model RE (Two-piece Inner Ring Type for Outer Ring Rotation)
Main dimensions are the same as model RB. This model is used in locations where the rotational accuracy of the outer ring is required.
USP-Grade Series of Models RB and RE
The rotation accuracy of the USP-Grade Series achieves the ultra precision grade that surpasses the world’s highest accuracy standards such as JIS Class 2, ISO Class 2, DIN P2 and AFBMA ABCE9.
Model RAU (Integrated Inner/Outer Ring Type)
The extremely small cross-sectional area allows it to be used in lightweight, compact devices. The integrated inner/outer ring structure can be used for both inner and outer ring rotation. There is a 5 mm thin type and an RA interchangeable type. The thin type product lineup starts at a micro-sized 10 mm inner diameter.
Model RA (Separable Outer Ring Type for Inner Ring Rotation)
A compact type similar to model RB with the thinnest possible inner and outer rings. It enables lightweight and compact designs for the swiveling hand portions of manipulators and robots.
Model RA-C (Single-Split Type)
The main dimensions are the same as that of model RA.Owing to its Single-split Outer Ring structure with a highly rigid outer ring, this model can be used for outer ring rotation.
