Thin-section bearings and crossed cylindrical roller bearings are two major categories of bearings used in industrial robots. Other types include harmonic drive bearings, linear bearings, and spherical plain bearings.
Bearings are critical components for industrial robots. They are suitable for a wide range of applications, including robot joints and rotating sections, rotary tables in machining centers, robotic arm swivel units, precision rotary tables, medical equipment, measuring instruments, and IC manufacturing equipment.
Characteristics of industrial robot bearings: ability to withstand combined loads (axial, radial, and moment loads); thin-section design; and high rotational positioning accuracy. Any bearing meeting these design requirements can be used in components such as robot arms, rotary joints, and bases.
Characteristics of crossed roller bearings: In these bearings, cylindrical or tapered rollers are arranged perpendicularly to one another-alternating at 90-degree angles-within V-shaped raceways, separated by spacers. Consequently, they can withstand loads from multiple directions, including radial, axial, and moment loads. Their inner and outer ring dimensions are minimized-with ultra-thin versions approaching the limits of compactness-while offering high rigidity and precision grades of P5, P4, or P2. They are therefore ideal for applications such as industrial robot joints and rotating units, rotary tables in machining centers, precision rotary tables, medical equipment, computing devices, military hardware, and IC manufacturing equipment.
1. Excellent rotational accuracy:
The internal structure features rollers arranged in a crossed pattern, perpendicular to one another at 90 degrees. Spacers or separators placed between the rollers prevent tilting and mutual friction, effectively preventing increases in rotational torque. Furthermore, issues such as roller skewing or locking are avoided. Since the inner and outer rings feature a split design, the clearance is adjustable; this ensures high-precision rotational movement even when preload is applied.
2. Simplified Installation:
The outer or inner ring is split into two sections; once the rollers and cage are inserted, these sections are secured together, making the installation process very simple.
3. High Axial and Radial Load Capacity:
Because the rollers are arranged perpendicularly to one another-separated by spacers-within V-shaped raceways set at a 90° angle, the crossed roller bearing design allows it to withstand loads from all directions, including radial, axial, and moment loads.
4. Significant Space Savings:
The dimensions of the inner and outer rings are minimized; the ultra-thin design pushes the limits of compactness while maintaining high rigidity. Consequently, these bearings are suitable for a wide range of applications, such as the joints or rotating sections of industrial robots, rotary tables for machining centers, robotic arm rotation units, precision rotary tables, medical instruments, measuring equipment, and IC manufacturing systems.
Thin-Section Bearings (Constant Section)
Thin-section bearings (constant section) comprise seven open series and five sealed series. The open series includes three types: radial contact (Type C), angular contact (Type A), and four-point contact (Type X). Advantages: These bearings feature an extremely thin cross-section, enabling compact and lightweight product designs. Their product diversity expands their range of applications.
Product Characteristics: Small-diameter steel balls are used to achieve low frictional torque, high rigidity, and excellent rotational accuracy. The use of a hollow shaft ensures a lightweight design and provides space for wiring. The thin-section 6700 and 6800 series offer a comprehensive range of options, including various dust shield configurations, flanged types, stainless steel versions, and wide-profile designs.
Main Applications: Stepper motors, medical equipment, office equipment, testing instruments, speed reduction/transmission units, industrial robots, optical/imaging equipment, and rotary encoders.
Also known as thin-ring bearings, these bearings offer high precision, quiet operation, and high load-carrying capacity. Thin-section bearings can be deep-groove ball bearings, four-point contact bearings, or angular contact ball bearings; most thin-section bearings feature a square cross-section. In these series, the cross-section remains constant even as the shaft diameter and bearing bore size increase-hence the designation "constant section." This characteristic distinguishes thin-section bearings (within standard ISO series) from conventional bearings. Consequently, one can select a larger cross-section and utilize a bearing with higher load-carrying capacity without altering the shaft diameter. Thin-section bearings can be designed to be extremely lightweight and compact, requiring minimal space.