Advantages, Precision Classification, and Grades of Cross Roller Ring Bearings
The Application Advantages of Cross Roller Ring Bearings
Outstanding Rotational Accuracy
The rollers are equipped with spacers or isolators between them to prevent tilt or mutual friction, effectively preventing an increase in rotational torque. This design avoids one-sided contact or seizure phenomena, while the split structure of the inner and outer rings allows for gap adjustment. Even when preload is applied, high-precision rotational movement is achieved.
Simplified Operation and Installation
The outer or inner rings, which are divided into two parts, are fixed together after the rollers and spacers are inserted, so the installation process is very simple.
Bearing Larger Loads
Due to the rollers being vertically arranged at 90° using spacers in the V-shaped groove rolling surface, this design allows cross roller ring bearings to bear large radial, axial, and moment loads in all directions.
Significant Space Saving for Installation
Cross roller ring bearings have been miniaturized in inner and outer ring dimensions, especially with an ultra-thin structure achieving near-limit miniaturization, and boast high rigidity. They are particularly suitable for joint parts or rotating parts of industrial robots.
Accuracy Classification of Cross Roller Ring Bearings
The accuracy of the cross roller ring bearing is divided into dimensional accuracy and rotational accuracy.
Dimensional Accuracy
This includes allowable deviation of the roller group's inner and outer pitch diameters, the allowable variation in width, the allowable deviation of width and assembly width, and the permissible limit of chamfer dimensions related to shaft and housing installation parameters.
Rotational Accuracy
This includes allowable lateral runout of the inner ring, allowable axial and radial runout of the inner and outer rings, allowable variation of the outer diameter surface inclination, allowable variation in thrust bearing raceway thickness, and allowable deviation and variation of the tapered hole related to bearing self-rotation runout parameters.
Accuracy Grades of Cross Roller Ring Bearings
In actual demand processes, different mechanical equipment requires different accuracy levels forcross roller ring bearings. To better meet these needs, cross roller ring bearings are divided into different accuracy grades:
Cross roller ring bearings are mainly classified into five accuracy grades: P0, P6, P5, P4, and P2. Each grade has different tolerance ranges and manufacturing requirements to suit different application scenarios.
P0 grade generally refers to bearings with rotational accuracy exceeding 10 microns and is widely used, such as in the speed control mechanisms of ordinary CNC lathes, feed mechanisms, car speed control mechanisms, large tractors' speed control mechanisms, as well as motor, centrifugal pump, and agricultural machinery's rotational mechanisms.
P6 and P5 grades are suitable for high-precision cross roller ring bearings with rotational accuracy between 5-10 microns or higher speeds. These are used in precision instrument equipment, dashboards and instruments, and precision rotating mechanisms.
P4 and P2 grades are suitable for high-precision cross roller ring bearings with rotational accuracy not exceeding 5 microns or even higher speeds, such as in precision coordinate milling machines, precision grinding machine transmission gear systems, and high-speed cameras in instruments and instrument panels.